Chess Training

SonofMarios — Building a balanced opening repertoire

Road to 800

Tiered ladder: 700 by May 31 · 750 by Jun 30 · 800 by Jul 31, 2026

Current → Next tier
718750 (+32 pts)
Apr 14 · start (530) · now 718May 31 · 700 ✓Jun 30 · 750Jul 31 · 800
The three rules that buy the points
1. When up material, TRADE
Before every move, ask "am I up material? Is there a trade available?" If yes, take it.
2. Count before you sortie
Before any forward piece move (Ng5, Qh5, Ne5), count attackers vs defenders of that square.
3. Don't castle into a storm
If opponent has played early ...h6 or ...g5, castle queenside or delay. Check their king first.
Weekly habit (~45 min total)
3-4 rated games at Rapid 30+0 or 15+10 (NO bullet/blitz during the climb)
1 game review per week — bring the worst game for dissection
10 tactics puzzles/day on Chess.com (5 min) — patterns for forcing moves
Tier 1 by May 31 (700) CLEARED: base habits installed, current ATH 718  ·  Tier 2 by Jun 30 (750): consolidate opp-gift management, install repetition-avoidance and don't-trade-active-piece rules  ·  Tier 3 by Jul 31 (800): opening depth (anti-London, Pirc Qa5+ motif), endgame conversion speed

Opening Tutors

Interactive step-by-step lessons with quizzes

The London System

Your main weapon as White. Covers the core setup, handling ...Bd6/e5, ...Bf5, ...Bg4 pin, middlegame plan, anti-Qb6, and traps & tactics (Greek Gift, hxg3 attack, Ne5, back-rank mate).

White7 tabs10 quizzes

The King's Indian Defense

Your system for Black — same setup against everything. Covers vs d4, vs e4, middlegame plans, and key principles.

Black4 tabs2 quizzes

The Caro-Kann

Solid alternative to the Pirc — active light bishop, sound structure, no kingside cracks. Covers Classical, Advance, Exchange, Panov-Botvinnik, Two Knights, and key principles for the entire opening.

Black6 tabs5 quizzesNew!

The Pirc Defense

Your KID-style answer to 1.e4 — same soul, trickier move order. Covers setup discipline, Classical Pirc, Austrian Attack (f4), the 150 Attack (Be3+O-O-O), and the Game 81 lesson walkthrough.

Black6 tabs5 quizzes

The Scandinavian Defense

Your second answer to 1.e4, alongside the Pirc. Classic 3...Qa5 main line: the queen recapture, the ...c6 and develop-the-bishop-before-...e6 rules, and the traps (why 4.b4 is a free pawn). Built from your own L21 ideas.

BlackMain Line + TrapsQuizNew!

The Sicilian Defense

Studied but secondary. Covers why 1...c5, the Open Sicilian, and a practical Najdorf development plan.

Black3 tabs1 quiz

The Italian Game

An earlier lesson covering classical e4 e5 play. Superseded by the London as your main White opening.

WhiteArchive

Wing Pawns: a & h Files

When to push the a- and h-pawns — and when to leave them alone. Covers pawn storms, space grabs, prophylaxis, and how to respond when your opponent pushes theirs. Works for both London (White) and KID (Black).

Universal5 tabs4 quizzesNew!

Endgame Training

The fundamentals that turn advantages into wins

Endgame Essentials

King+pawn endings (opposition, rule of the square), rook endings (Lucena, Philidor), when to trade, how to convert wins, and stalemate avoidance. The 20% of endgame knowledge that covers 80% of practical situations.

5 tabs34 positionsNew!

Training & Review

Practice, train, and track your progress

Game Reviewer

Paste any PGN and step through every move on a visual board. See exactly where pieces are at each point in the game.

PGN parserStep-throughNew!

Tactics Trainer

16 puzzles built from your actual game mistakes. Trades, checks, defence, back-rank awareness — train the patterns that cost you games.

Your games16 puzzles6 categories

Post-Game Review

Structured self-analysis with a built-in board viewer. Step through your game and answer reflection prompts before getting coached.

7 stepsSelf-analysisNew!

Progress Dashboard

Stats, trends, and pattern tracking across all 271 games. See what's improving, what's stuck, and what to focus on next.

271 gamesTrendsNew!

CCT & Conversion Drill

Daily 5-minute habit built from your own games. Find the clean move, not the flashy check. Trains the Capture-Checkmate-Tactic scan with a day-streak tracker.

10 puzzlesDailyNew!

Blundercheck Trainer

The complement to the CCT drill. Eight positions from your own games, each right before a real mistake. The skill: check what your move allows before you commit. Trains defence and threat-spotting, not just tactics.

8 puzzlesYour blundersNew!

Training Centre

11 interactive scenarios that teach you WHY to play each move. Covers bishop defense, London attacks, KID foundations, and endgame technique.

11 scenarios4 categories

Strategy Trainer

11 exercises on KID attack plans (Hikaru method), Capablanca's conversion principles, and pawn play. Built from your game patterns.

11 exercises3 themesNew!

Practice Positions

5 quick-fire quizzes on board strategy. Where should you focus your play?

InteractiveVisual boards

Coaching Report

Strengths, patterns to break, skills to build — based on all reviewed games.

271 games analysed

Player Studies

Deep dives into Hikaru Nakamura's KID attack blueprint and Capablanca's positional principles — tailored to your game.

HikaruCapablancaNew!

My Opening Repertoire

Current openings and their key ideas

White: The London System

The Setup (same every game)

1. d4 — Claim the center

2. Bf4 — Dark bishop out BEFORE e3

3. e3 — Support d4, open light bishop diagonal

4. Nf3 — Develop knight, prepare castling

5. Bd3 — Light bishop, eyes h7

6. O-O — King safety

After Castling Priorities

Nbd2 (always first) → c4 (challenge d5, soften the center) → e4 (the big break, comes easy once d5 is gone) → Re1 (if needed) → Qc2 (later, battery with Bd3)

Key Rules

Don't chase pieces on the rim. Recapture e4 with knight first. When a pawn kicks your bishop, retreat to a good square — don't trade without reason. When opponent attacks one side, counter on the other.

⚠️ vs ...Nc6: play c3 BEFORE e3. Prevents Nb4→Nc2+ fork (lost Games 60, 64, 78). If Nb4 already happened: Na3 (controls c2, enables recapture).

Black: The King's Indian Defense

The Setup (works against everything)

1. Nf6 — Knight first (d6 first vs e4)

2. g6 — Prepare fianchetto

3. Bg7 — The star piece

4. d6 — Support ...e5

5. O-O — King safety

Middlegame Plan

Push ...e5 to challenge the center. After d5 closes things: kingside is YOUR territory. Push f5, knights to f4, rooks on f-file. White attacks queenside, you attack kingside — it's a race.

Key Rules

NEVER trade the Bg7. Let White build a big center, then attack it. Big centers are big targets. Castle by move 5-6 always.

Practice Positions

Choose the right plan for each scenario

= White = Black

Coaching Report

Ongoing assessment based on 271 games (updated Jun 13, 2026)

What You're Doing Well

London System is locked in

92% of your White games use the London. The setup is becoming automatic — d4, Bf4, e3, Nf3, Bd3, castle, Nbd2. You're not thinking about what to play anymore, you're just doing it. That's exactly where we want to be.

You find attacking patterns

The Bxh7+ Greek Gift sacrifice, the Ng5/Qh7+/Qh8# battery, the e4 break timed correctly — these aren't accidents. You're recognising London attacking motifs in real games. Multiple wins came from clean, principled attacks after a solid setup.

You never give up

Several games where you were down material, you fought back and won or drew. That mental toughness is a genuine competitive advantage at every rating level.

Bishop defense is clicking

Two consecutive games where Black challenged your Bf4 — ...g5 (vs 1200 bot) and ...Bh6 (vs live opponent) — and both times you played Bg3 without hesitation. This was your biggest weakness three games ago and now it's automatic. The training is working.

Endgame grinding is a real weapon

Against the 1200 bot, you were down material from the middlegame but created three passed pawns (d6, b6, h-file), promoted two queens, and delivered checkmate. That's not luck — that's technique. You know how to push pawns, create threats on multiple fronts, and convert. This is becoming a genuine strength.

You know when you've gone wrong

Your post-game self-analysis is consistently accurate. You spotted the queenside castling miss, the passive bishop retreats, and the piece-chasing before being told. That self-awareness accelerates improvement.

Patterns to Break

1. Don't check just because you can

Multiple games show checks played automatically (Bb5+, random discovered checks) that waste tempo and help the opponent develop. Before playing a check, ask: "Does this actually improve my position, or am I just checking because I can?" A check that doesn't gain something concrete is often a wasted move.

2. Protect the London bishop — don't trade it cheaply ✓ IMPROVING

Two recent games show correct Bg3 retreats against ...g5 and ...Bh6 — this was your biggest weakness and it's now clicking. Keep drilling: if ...g5 attacks it, retreat Bg3. If ...Bh6 or ...Bd6 challenges before e3, play Bg3 first. If ...c4 kicks Bd3, retreat to Bc2. The reflex is building — don't let it slip.

3. Retreat to ACTIVE squares, not safe squares

When a piece gets attacked, the instinct is to put it somewhere "safe." But safe and passive often means the piece does nothing for the rest of the game. The key question is: "Where does this piece do the most work?" Bc4 over Be2. Nc4 over Nb3. Bc2 over Be2. Active pieces win games, passive pieces watch.

4. Don't open lines where they're attacking

When the opponent has pieces aimed at one side of the board, never open files or diagonals on that side. Pushing g3 when their rook is on the g-file, or pushing e4 into their f5 pawn — these moves hand them exactly what they want. Play on the OTHER side of the board instead.

5. Don't meet aggression with aggression

When the opponent throws everything at your king, the natural instinct is to fight back there. The winning response is almost always to counterattack where they've left themselves weak. They push kingside? You play queenside. They commit pieces to one flank? The other flank is undefended. Make them regret overcommitting.

6. Never push f3 in the London

Against the 1200 bot, f3 weakened the king's diagonal and Black immediately punished with Qe3+, winning the Bd3. In the London, your f-pawn should almost never move — it guards g2 and keeps the e1-h4 diagonal safe. If Black pushes ...g4 to kick your knight, let the knight go to d2 or e5. Challenge g4 later with h3 instead of f3. The f-pawn is a wall, not a battering ram.

7. Use c4 to prepare e4 — the two-step central plan

In the live game vs wilpol, the e4 break cost the Bd3 because the recapture sequence went wrong. The cleaner plan: push c4 first to challenge Black's d5 pawn. Once the d-pawn is traded off, e4 comes for free — no captures, no sacrifices, and your Nd2, Bd3, Qf3 all stay on their best squares. If the queen is on f3 (blocking Nd2→f3), that's fine — the knight supports e4 from d2 and doesn't need to move. c4 softens the center, e4 takes it over. Two steps, no material cost.

8. Check piece safety AFTER every tactic

After a tactical sequence (winning material, making a sacrifice, a series of exchanges), pause and scan the whole board. Are any of your pieces hanging? Can anything be taken for free? Several losses came from winning a tactic but leaving a piece unprotected in the aftermath.

9. Don't trade your best-placed piece for a check

In game 26, you had a knight beautifully centralised on d4 — the strongest piece on the board. You played Nf3+ because it was a fork, but White just captured with the queen and your best piece was gone for nothing. A check or a fork is only good if it wins material or creates a lasting advantage. If it just trades your best piece for a tempo, it's a bad deal. Ask: "Is this piece doing more where it is than what I'm getting by moving it?"

10. Bc2 when the light bishop is kicked — NEVER Bc4

Game 27: after ...e4 kicked the Bd3, you played Bc4 — and Black's d-pawn just took it for free (dxc4). The bishop belongs on Bc2: same b1-h7 diagonal, can't be captured, still aims at the kingside. This is a concrete rule: when any pawn kicks your light bishop, retreat to Bc2. Not Bc4. Not Be2. Not Bf1. Always Bc2.

Skills to Build Next

Converting winning positions ✓ IMPROVING

Previously three games ended in draws from winning positions, but the bot game showed excellent conversion: down material, you created multiple passed pawns, promoted calmly, and delivered checkmate. The live game was also clinical — piece activity into resignation. Keep it up: trade pieces, push passed pawns, and don't get fancy.

Basic endgame technique

You stalemated an opponent with Q+2P vs bare King. In K+Q vs K: keep your queen a knight's move away from their king, use your own king to help restrict them, and always leave them at least one legal move until you're ready to checkmate. This alone will convert several draws into wins.

KID move order as Black ✓ IMPROVING

Move order is now locked in — games 26, 29, and 30 all opened correctly (d6 first vs e4). The next challenge is the middlegame plan. Game 29: played ...e6 (wrong break — should be ...e5) and ...d5 walked into e5! costing a piece. Game 30: didn't protect Bg7 from White's h-pawn storm (h6 threat). The KID breaks are ...e5 (challenge the center) and ...f5 (kingside attack after d5 closes the center). Never play ...e6 — it opens the position in White's favor. 0W, 1D, 4L — but the openings are solid now.

Where to castle

Default is kingside, but when the opponent has pushed pawns at your kingside (f5, g5, h5 type moves), castle queenside instead. Don't walk your king into their attack. Read the pawn structure BEFORE castling and choose the safer side.

Pre-Game Checklist

White? London. d4, Bf4, e3, Nf3, Bd3, O-O, Nbd2, then e4.

Black vs 1.e4? KID. Play d6 first, then Nf6, g6, Bg7, O-O.

KID after d5? Break with ...e5, NOT ...e6. Or prepare ...f5 kingside attack (Nd7 first).

Black vs 1.d4? KID. Play Nf6 first, then g6, Bg7, d6, O-O.

Before every move: Is anything hanging? Is there a tactic? Then play your plan.

When attacked: Don't fight on their terms. Find where they're weak and play THERE.

When winning: Trade pieces. Push pawns. Don't get fancy. Close it out.

Player Studies

Lessons from the greats, tailored to your games and weaknesses

Hikaru Nakamura — KID Attack Blueprint

Why Hikaru?

Hikaru is one of the strongest modern King's Indian players. His approach distills the KID middlegame into a repeatable pattern you can follow every game once the center closes.

The Attack Sequence

After the standard KID setup (Nf6, g6, Bg7, d6, O-O, e5), White usually closes the center with d5. From that moment, your plan is always the same:

1. Reposition the Nf6 — play ...Nd7 (best) or ...Nh5. The knight must clear the f-file.

2. Play ...f5 — this is the KID's big break, equivalent to the London's e4. Everything builds toward this.

3. After ...f5: if White takes (exf5), recapture ...gxf5 and the g-file opens for your rook. If White doesn't take, push ...f4 to lock the kingside.

4. After ...f4: push ...g5 then ...g4 — the "battering ram" that rips open lines to White's king.

5. The "Magic Number": before crashing through, get 3+ attacking pieces aimed at the king — Ng6 or Nf4, rook(s) on the f-file, Bg7 on the long diagonal. Don't launch until the pieces are ready.

Model Games

Hikaru vs Gelfand (Tal Memorial 2010) — Classic KID kingside attack showing the full sequence: setup, f5 break, f4 lock, g5-g4 storm, pieces crash through. The blueprint from start to finish.

Hikaru vs Wesley So (2015) — Demonstrates patience. Built up the kingside slowly, waited for the right moment, then broke through with f5. Shows that the KID attack is about SETUP, not rushing.

How This Applies to You

Your KID games (26, 29, 30, 31) show good opening setup but the middlegame plan was missing until Game 31. The Hikaru blueprint gives you the plan: after d5 closes the center, it's always knight repositions → f5 → f4 → g5 → g4 → pieces attack. Game 31 showed the first signs of this — centralisation, opening lines, tactical finish. Now add the f5 break to your arsenal.

Key Principle

"The KID attack isn't about rushing forward — it's about getting the setup right and THEN crashing through. Setup before strike."

Capablanca — Converting Advantages

Why Capablanca?

Capablanca was the third World Champion and the greatest positional player of his era. His style was clever and efficient, not overly aggressive — exactly what you need to balance your natural attacking instinct. His core philosophy: "When winning, make it simple."

1. Simplify When Winning

When ahead in material or position, trade pieces. Fewer pieces on the board means fewer ways your opponent can trick you. Don't keep everything on looking for more tactics when you already have enough advantage to win. This directly addresses Games 8 (loss despite being up material), 10 (stalemate with Q+2P vs nothing), and 28 (missed mate-in-2).

2. The "What Do They Want?" Pause

Before every move, spend 5 seconds asking: what is my opponent trying to do? What does their last move threaten or prepare? This single habit would have prevented the 8...Bxd5 disaster in Game 19 (opened lines against own pieces) and the 12...Nf3+ blunder in Game 26 (traded best piece for a meaningless check).

3. The Principle of Two Weaknesses

Attacking one weakness usually isn't enough — your opponent parks a defender there. Create a second weakness on the other side of the board, then alternate threats until they can't defend both. Relevant to London middlegames where you sometimes get stuck attacking one side with no plan B.

4. King Activation

The moment queens are traded, the king becomes an attacking piece. Move it toward the center immediately — Kf1, Ke2, Kd3 (or the mirror for Black). At your level, the player who centralises their king first in the endgame almost always wins. This is the #1 endgame habit to build.

5. Piece Activity Over Material

A well-placed piece is worth more than a pawn. A knight on d4 controlling the center is more valuable than grabbing a wing pawn. This connects to Game 26 (Nd4 traded for nothing) vs Game 31 (Nd4 kept and dominated the whole game). Don't trade active pieces for passive gains.

Three Habits to Build

Every 5 moves: "Am I winning?" → If yes, look to trade a pair of pieces. Don't add complexity.

Every move: "What do they want?" → 5 seconds identifying opponent's threats before playing yours.

Queens come off: King goes to the center. Immediately. No exceptions.

How Hikaru + Capablanca Work Together

Hikaru teaches how to ATTACK in the KID — the f5 break, the pawn storm, the magic number of attacking pieces. Capablanca teaches what to do AFTER the attack succeeds — simplify, trade pieces, activate the king, push passed pawns. Together they cover the full game arc: opening setup → middlegame attack → conversion → endgame technique.

Key Principle

"In order to improve your game, you must study the endgame before everything else." — Capablanca

Chess Dictionary

Every term you've seen in a review, explained plainly. Use Ctrl-F to find a word fast.

Tactical Motifs
Fork (double attack)
A single piece attacks two or more enemy pieces simultaneously. Knights are the classic forking piece because they attack in an L-shape — hard to defend against. Example: a knight on e5 forking the king on g8 and the rook on c6.
Pin
A piece is "pinned" when moving it would expose a more valuable piece behind it to attack. An absolute pin is against the king (the pinned piece literally cannot move — illegal to expose your own king). A relative pin is against a more valuable piece (you can move, but you'd lose material).
Skewer
Like a reverse pin — the more valuable piece is in FRONT. When it's attacked, it has to move, revealing a less valuable piece behind that then gets captured. "Shish-kebab" of two enemy pieces on one line.
Discovered Attack
When moving one of your pieces uncovers an attack from a DIFFERENT piece behind it. Very powerful because you're making two threats in one move. A discovered check is when the uncovered piece gives check to the king.
Double Check
A rare and devastating discovered attack where BOTH the moving piece AND the uncovered piece give check at the same time. The king MUST move — capturing or blocking can only address one checker.
Zwischenzug (German: "in-between move")
Also called an intermezzo. A forcing in-between move (usually a check or capture) inserted BEFORE the expected recapture. Lets you grab extra material or tempo. Example from Game 40: 16...Nxd4 expected Qxd4 recapture, but you played 17.Ncd6+ FIRST forcing Kf8, THEN 18.Qxd4 — winning the castling rights bonus.
Deflection
Forcing an enemy piece AWAY from a square it was defending, so you can then exploit the undefended square. "Getting rid of the bodyguard."
Decoy (attraction)
The opposite of deflection — luring an enemy piece TO a bad square (often by sacrificing something) so it can be attacked or used in a combination.
Battery
Two (or more) of your long-range pieces stacked on the same line — queen behind bishop on a diagonal, or queen behind rook on a file. Multiplies attacking power on that line. The classic London battery is Qc2 + Bd3 aiming at h7.
Overloaded Piece
A defender that's doing too many jobs at once. If it's defending two things, you can attack one of them to force it to choose — whichever it saves, you win the other.
X-Ray
When a piece defends or attacks THROUGH another piece. A rook on a1 "x-rays" a knight on a5 if the knight were removed.
Sacrifice
Giving up material for a non-material gain (attack, position, initiative, checkmate). A real sacrifice has no forced return of material — you're betting on long-term compensation. A sham sacrifice wins the material back (or more) by force.
Quiet Move (quiet killer)
A move that isn't a check or capture, but creates a devastating threat — often more dangerous BECAUSE the opponent doesn't see it coming. Example: 21...Bd5!! in Game 57 — the bishop retreated (quiet), escaping a threat while simultaneously creating a new one (attacking g2 and blocking the d-file). Quiet killer moves are the hardest to spot because they don't trigger your "danger alarm."
Rook Lift
Moving a rook from the back rank to the 3rd or 4th rank, then swinging it sideways to attack. The classic London rook lift is Rf1→f3→h3 after hxg3 opens the h-file. At 500-700, opponents almost never expect a rook on the 3rd rank — it's a surprise weapon.
Counting Attackers vs Defenders
Before capturing on a square, count how many of YOUR pieces attack it and how many OPPONENT pieces defend it. If you have more attackers, the capture wins material. If they have more defenders, you lose material. Sounds obvious but it's the #1 tactical skill at your level — failed in Game 53 (missed the Nd2 defender), succeeded in Game 57 (correctly counted Qxe5 winning the knight).
Swindle
Winning (or drawing) a game from a losing position because your opponent makes a mistake — NOT because your play was sound. A swindle is still a result, but it's NOT proof that your plan worked. Game 56 was a swindle: the queen raid only won because the opponent missed a simple ...g6 defence. Honest training means labelling swindles correctly.
Positional Concepts
Tempo
A "unit of time" — one move. Gaining a tempo means making a useful move while forcing your opponent to waste one (e.g. developing a piece with check). Losing a tempo means making a move that accomplishes nothing, or moving a piece twice when it shouldn't have moved.
Initiative
The ability to make threats that your opponent must respond to. The side with the initiative dictates the pace of the game. Lose the initiative → you're defending → you're on the back foot.
Prophylaxis
A move that PREVENTS your opponent's plan before it happens, rather than making your own threat. Example: playing h3 to stop a future ...Bg4 pin. "Stopping their plan is as good as making your own."
Outpost
A square for a piece (usually a knight) that CANNOT be attacked by enemy pawns. Outposts supported by your own pawns are permanent — that's the dream. Example: a knight on d5 or e5 in the London.
Luft (German: "air")
Breathing room for the king. A pawn move like h3 or g3 that prevents back-rank mate by giving the king an escape square. Worth playing pre-emptively when queens + rooks are on the board.
Bishop Pair
Having BOTH bishops (light-squared AND dark-squared) while your opponent has only one. Worth about +0.5 pawns of positional value (Kaufman's engine analysis) on top of standard piece values. Bishops work best together on opposite colours — they cover everything between them.
Space
The total area of squares your pieces control behind your pawn chain. More space = more room to manoeuvre. Count pawns on your opponent's half of the board — the side with more is "up on space."
Centralisation
Placing pieces in or near the centre, where they control the most squares. A knight on d4 covers 8 squares; a knight on h1 covers 2. In endgames, centralising the king is often the winning move.
Piece Activity
How useful your pieces ARE, not just where they're placed. An active bishop on a long diagonal beats a trapped bishop hiding in the corner. "Activity over material" is often the deciding factor at the club level.
Weakness
A pawn or square you can't defend properly. Weak pawns (isolated, doubled, backward) and weak squares (squares your pawns can no longer defend) become long-term targets.
Simplification
Trading pieces to reduce complexity. Golden rule: when ahead in material, trade PIECES (not pawns). When behind, trade PAWNS (not pieces). Simplification converts a material edge into a higher-percentage winning position.
Pawns & Pawn Structure
Passed Pawn
A pawn with no enemy pawns on its file OR on adjacent files between it and promotion. "Passed pawns must be pushed." They're the endgame's deciding factor.
Doubled Pawns
Two of your pawns on the same file (a result of a capture). Generally a minor weakness — they can't defend each other and one blocks the other's advance. Sometimes acceptable if the capture opened a useful file (see Game 43 axb3 discussion).
Isolated Pawn (isolani)
A pawn with no friendly pawns on ADJACENT files. Weak because no pawn can ever defend it — only pieces can.
Backward Pawn
A pawn that can't advance safely because the square in front is controlled by enemy pawns, AND it has no friendly pawn alongside to protect it. Often sitting on a half-open file, which means rooks attack it.
Pawn Storm
An attack using pawn advances (typically h4-h5-h6 or g4-g5) to break up the enemy king's shelter. Only effective when your king is on the OTHER side of the board, or when you haven't castled yet.
Pawn Break
A pawn push that challenges the enemy pawn structure and opens the position. The London's e3-e4 is the classic example — it's THE move your whole opening builds toward.
Open File / Half-Open File
A file with no pawns on it (open) or with only enemy pawns (half-open). Rooks love open files because they can travel the full distance unblocked. "The rook belongs on the open file."
Openings & Development
Development
Bringing your pieces from their starting squares into the game. The opening is essentially a race to complete development. General rule: minor pieces (knights and bishops) before queen, castle before launching attacks.
Castling
The only move where you move two pieces at once (king + rook). Kingside (O-O) is short castling; queenside (O-O-O) is long castling. Achieves king safety AND rook activation in one move.
Fianchetto (Italian: "little flank")
Developing a bishop to the long diagonal by first playing g3/g6 (or b3/b6), then placing the bishop on g2/g7 (or b2/b7). The KID's Bg7 is a fianchetto — the bishop's ideal square.
Gambit
An opening where one side deliberately sacrifices material (usually a pawn) for development or initiative. The Queen's Gambit (1.d4 d5 2.c4) is the most famous.
Sortie
Sending a piece forward into enemy territory, usually aggressively. A queen sortie (early Qh5) or knight sortie (Ng5) are the most common. Carries a cautionary tone — sorties without a concrete plan often lose tempo as the piece gets chased back.
Opening Principles
The three classical rules: (1) control the centre with pawns, (2) develop your minor pieces toward the centre, (3) castle early for king safety. Don't move the same piece twice in the opening unless forced.
Attacks & King Safety
Check
Attack on the king. Must be addressed immediately: move the king, block the check, or capture the checking piece.
Checkmate (mate)
The king is in check AND has no legal way to get out. Game over.
Stalemate
It's your turn but you have NO legal moves, AND you're NOT in check. Draws the game. Often a lifesaver for the losing side — always check for stalemate traps in endgames.
Back-Rank Mate
Checkmate delivered by a rook or queen on the 8th rank (or 1st for Black) when the king has no pawn-created escape. Prevention: play luft (h3 or g3) to give the king an out.
Greek Gift (Bxh7+)
A classical sacrificial pattern where White sacrifices the light-squared bishop on h7 (against Black's castled king) to open a mating attack with queen and knight. Only works when specific preconditions are met — not a "try it anyway" sac.
The Two-Bishop Advantage
See "Bishop Pair" above — same concept. Having both bishops vs opponent's bishop + knight gives roughly +0.5 pawn of long-term positional value.
Endgame Terms
Opposition
In king-and-pawn endings, when the two kings face each other with one square between them — the player NOT to move has "the opposition" and controls the other king's movement. Winning or drawing many endgames comes down to who has the opposition.
Zugzwang (German: "compulsion to move")
A position where any move you make worsens your position — but you're FORCED to move because it's your turn. The opposite of a "pass" card. Usually decides endgames with few pieces.
Triangulation
A king manoeuvre in pawn endgames — moving your king in a triangular path to reach the same square but with the OPPONENT to move, putting them in zugzwang. Advanced technique but essential in K+P endings.
Lucena Position
A winning rook-and-pawn endgame technique (rook + a/b/c/f/g/h pawn vs rook). The "building-a-bridge" method — your rook shelters the king as it escorts the pawn home. Textbook knowledge.
Philidor Position
The DRAWING technique for the defender in rook-and-pawn endgames. Keep your rook on the 3rd rank (from your side) until the enemy pawn advances, then swing behind for side checks. Saves many "lost" endgames.
Exchange (as noun)
Trading a rook for a bishop or knight. "Up the exchange" means you took the rook, gave the minor piece — worth about +2 pawns. Not to be confused with "an exchange" meaning any trade of equal pieces.
Rule of the Square
A quick visual trick to check if a king can catch a passed pawn: draw a mental square from the pawn to the promotion square. If the defending king is inside the square (or can step into it on their turn), they catch the pawn. If they're outside, the pawn promotes. Saves you from counting moves in your head during time pressure.
Tarrasch Rule
Rooks belong BEHIND passed pawns — yours OR your opponent's. Behind your own passed pawn: the rook supports the pawn's advance and gains space as the pawn pushes forward. Behind the enemy's passed pawn: the rook has maximum checking distance and the pawn blocks the opponent's rook. Named after Siegbert Tarrasch.
King Activation
In the endgame, your king transforms from a piece that hides behind pawns into a fighting piece that belongs in the centre. A centralised king in the endgame is worth roughly a minor piece in attacking power. The moment queens come off the board, think: "Where should my king go?" Usually the answer is the centre or toward the action.
Notation & Game Phases
PGN (Portable Game Notation)
The standard text format for chess games. Headers (Event, Date, White, Black, Result) followed by the move list in algebraic notation. Every game on Chess.com can be exported as PGN and pasted into the Game Reviewer.
Algebraic Notation
The standard way to write moves. Files are letters (a-h), ranks are numbers (1-8). Piece letters: K=King, Q=Queen, R=Rook, B=Bishop, N=Knight (pawns have no letter). Examples: e4 = pawn to e4, Nf3 = knight to f3, Qxd5 = queen takes on d5, O-O = kingside castle.
Half-Move (ply)
A single move by one side. A full "move" in chess actually consists of two half-moves (one by White, one by Black). The Game Reviewer uses half-move indices for its clickable badges: White move N = half-move (2N-1), Black move N = half-move 2N.
Opening / Middlegame / Endgame
The three phases of a chess game. Opening (~moves 1-12): development, king safety. Middlegame (~moves 12-30): tactics, pawn breaks, attacks. Endgame: few pieces left, king becomes active, pawns promote. Each phase has different priorities — the skills don't transfer automatically.