1. Blitz Chess
Changed:
- clock.
Not:
- variant.
2. Swiss Chess
Changed:
- tournament pairing.
Not:
- variant.
3. Chess960 Blitz Swiss
Ruleset:
- Chess960.
Clock:
- blitz.
Format:
- Swiss.
Lesson: three dimensions.
4. Correspondence Chess960
Ruleset:
- Chess960.
Mode:
- correspondence.
ICCF 2026 provides real institutional example.
5. Blindfold Standard
Rules:
- orthodox.
Display:
- hidden from player.
State:
- objectively complete.
6. Kriegspiel
State:
- deliberately hidden by rule.
Lesson: blindfold ≠ hidden information.
7. Random Back Rank
Bishops both on dark squares.
Not:
- Chess960.
8. Valid Chess960 Start
Bishops opposite colours. King between rooks. Black mirrors.
9. Orthodox Start in Chess960
Valid member of 960.
Lesson: randomized family includes standard array.
10. Chess960 c-Side Castle
Final:
- Kc1;
- Rd1.
Independent of starting files.
11. Chess960 g-Side Castle
Final:
- Kg1;
- Rf1.
12. King-Only Castle
Rook already on destination.
Still:
- castling move.
13. Rook-Only Castle
King already on destination.
Still:
- castling move.
14. Transposition Castle
King/rook swap positions.
FIDE-supported case.
15. Ordinary FEN Ambiguity
Two Chess960 rooks. KQ interpreted inconsistently.
Lesson: declare FEN dialect.
16. Freestyle Event
Brand:
- Freestyle Chess.
Rules:
- Chess960.
Lesson: brand ≠ ruleset ontology.
17. Chess960 Opening
No memorized e4 Sicilian tree.
Still:
- concrete preparation after start revealed.
18. Crazyhouse Capture
Captured knight:
- changes ownership;
- enters capturer pocket.
19. Crazyhouse Drop
N@e5.
No origin square.
20. Crazyhouse Drop Block
Line check blocked by pocket bishop.
Legal under current profile.
21. Crazyhouse Pawn Drop
Cannot drop on rank 1/8 under current Lichess.
22. Promoted Crazyhouse Pawn Captured
Returns as pawn in current Lichess.
Lesson: identity state.
23. Crazyhouse Queen on Board
Could be:
- original queen;
- promoted pawn.
Board glyph insufficient.
24. Bughouse Capture
Piece goes:
- partner pocket.
Not capturer pocket.
25. Bughouse Partner Colours
One teammate White on one board; Black on other.
26. Bughouse Piece Request
Need knight.
Communication/strategy layer.
27. Bughouse Cross-Board Sacrifice
Sacrifice rook here to give partner rook there.
Global evaluation.
28. Bughouse Sit
Player waits for partner capture.
Clock coupling matters.
29. Chess.com Bughouse
Current implementation:
- match can end when either board ends by mate/resign/timeout.
Do not universalize to every club.
30. Crazyhouse vs Bughouse
Same drop family. Different ownership graph.
31. Three-Check 0–0
Same board as 2–0 checks.
Different game state.
32. Double Check
Two attacking pieces.
Current Lichess:
- one check event.
33. Third Check
Legal checking move:
- immediate variant win.
34. KOTH Illegal Entry
King moves to d4 while attacked.
Not a win:
- move illegal.
35. KOTH Legal Entry
Ke4 legal.
Immediate variant win.
36. KOTH Checkmate
Still wins before hill reached.
37. Antichess Capture Available
Quiet move:
- illegal.
38. Antichess King in Check
Current Lichess:
- no special constraint.
39. Antichess King Captured
Legal possibility because king non-royal.
40. Antichess Castle
Current Lichess:
- unavailable.
41. Antichess Promote to King
Allowed current Lichess profile.
42. Antichess Extra Material
Can be disadvantage.
43. Losing Chess on Another Site
Royal king retained.
Same family label; different ruleset.
44. Atomic Capture
Capturer + target disappear.
45. Atomic Collateral Bishop
Adjacent bishop:
- explodes.
46. Atomic Collateral Pawn
Adjacent pawn:
- survives in current Lichess.
47. Atomic King Shield
Enemy piece beside king can be exploded.
Indirect king attack.
48. Atomic Adjacent Kings
Can be legal under current Lichess.
Lesson: orthodox king geometry broken.
49. Atomic Queen Value
Queen beside king becomes liability.
Material table insufficient.
50. Horde White
36 pawns in current Lichess.
Objective:
- mate Black.
51. Horde Black
Normal army.
Objective:
- eliminate Horde.
52. Horde Promoted Unit
Still belongs to Horde; must be eliminated for Pieces-side win.
53. Horde Balance
Armies asymmetric.
Can still be meaningful competitive game.
54. Racing Kings Check
Move gives check.
Illegal.
55. Racing Kings White Reaches 8th
Black gets immediate compensation reply.
56. Racing Kings Both Reach
Current Lichess:
- draw.
57. Racing Kings Material Win
Capturing queen may be irrelevant if race lost next move.
58. Fog of War
Opponent piece outside visibility:
- hidden.
59. Platform Fog
UI defines what you can see.
Rules + interface coupled.
60. Blindfold
Opponent piece not visually displayed.
But known from move history.
61. Four-Player Teams
Fixed ally across board in Chess.com current implementation.
62. Four-Player FFA
No fixed ally. Point/scoring objective.
63. Four-Player Solo
Platform-specific rating/mode variant.
Lesson: 4PC family.
64. Clockwise Turn
Threat must survive two intervening opponent/other-player moves.
65. Eliminated Army
Can become dead/frozen/removed depending implementation.
State must record rule.
66. Temporary FFA Alliance
Not encoded team.
67. Bughouse Global State
Two boards + pockets + clocks + team map.
Pair of FENs alone insufficient.
68. 10×8
Extra files change center and line distance.
69. Chancellor
Rook + knight movement.
Name can vary.
70. Archbishop
Bishop + knight movement.
Name can vary.
71. Same Name, Different Compound
Never trust display name alone.
72. Capablanca Family
10×8 + compounds.
Exact setup/castling sourced.
73. Grand Chess
10×10 distinct system.
Not simply:
- enlarged Capablanca.
74. Seirawan Chess
8×8 + reserves + gating.
75. Gating
Reserve piece enters as home piece vacates eligible square.
76. Cylinder Chess Rook
Line can cross a/h join.
Orthodox edge heuristic fails.
77. Alice Chess
Move transfers piece between boards.
Board ID part of state.
78. Hexagonal Chess
Three line axes.
Orthodox diagonal/orthogonal ontology incomplete.
79. Shatranj
Historical playable reconstruction.
Need:
- source model.
80. Shogi
Independent living chess-family tradition.
Not:
Crazyhouse Japan.
81. Shogi Capture
Captured piece can later drop for capturer under shogi rules.
82. Shogi vs Crazyhouse Pawn Drop
Different restrictions.
Lesson: mechanic similarity ≠ rules identity.
83. Xiangqi Cannon Move
No capture:
- rook-like.
84. Xiangqi Cannon Capture
Requires exactly one screen.
85. Xiangqi General Facing
Empty file between generals:
- illegal/constraint.
86. Xiangqi River
Changes piece behavior/regions.
87. Janggi
Related to xiangqi, but distinct palace/cannon/elephant rules.
88. Makruk
8×8 does not imply orthodox chess.
Piece/pawn/endgame rules differ.
89. Regional Comparison
Use own game first; FIDE comparison second.
90. Postal Correspondence
Remote transmission over long reflection periods.
Mode.
91. ICCF Server
Server handles timestamps/claims.
Still:
- correspondence mode.
92. Correspondence Engine Policy A
Event permits tools.
93. Correspondence Engine Policy B
Event forbids engine.
Lesson: authority-specific.
94. ICCF 7-Piece Claim
Current ICCF has certified tablebase claim procedure.
Not:
- ordinary FIDE OTB rule.
95. Blindfold Simul
Mode A:
- blindfold.
Mode B:
- simultaneous.
Both apply together.
96. Accessibility Blind Mode
Screen reader presents full state.
Not:
- blindfold contest.
97. Consultation Chess
Team deliberates. One move submitted.
98. Bughouse
Team members independently move on two boards.
Not consultation.
99. Material Odds
Start without rook.
Handicap form.
100. Time Odds
Same board; unequal clocks.
Clock handicap.
101. Rule Delta
Crazyhouse:
- capture → reserve.
Immediate consequence:
- material never simply leaves game.
102. Broken Heuristic
Trade queens to reduce attack.
Crazyhouse:
- queen may return through drop.
Needs re-evaluation.
103. Three-Check Sacrifice
Give material for second/third check.
Objective changes value.
104. Antichess Hanging Piece
Good:
- opponent forced to take.
Orthodox heuristic inverted.
105. Atomic Protected Piece
Protection irrelevant if collateral blast wins king.
106. Racing Kings King Exposure
Check concept absent; route speed dominates.
107. Transfer Skill
Calculation discipline transfers.
Exact evaluation:
- may not.
108. Rule Reset
After Antichess: remember check exists again in orthodox.
109. PGN Variant Tag
Parser reads:
- variant first;
- moves second.
110. Chess960 Castling Export
Round-trip retains rook identity/rights.
111. Crazyhouse Pocket FEN
Board same; different pocket.
Different state.
112. Three-Check Counter
Board same; counter differs.
Different state.
113. Multiplayer Turn
Same board; different next player.
Different state.
114. Hidden View
Player-visible board:
- not authoritative full state.
115. Stockfish Chess960
UCI_Chess960=true.
Correct profile.
116. Stockfish Atomic
Official Stockfish:
- wrong engine choice.
117. Fairy-Stockfish Atomic
Variant-capable engine/profile.
118. Fairy-Stockfish Custom Variant
INI defines new pieces/start/rules at runtime.
119. Engine Version Mismatch
New variants.ini; old binary.
Config options unsupported.
Lesson: binary + config version together.
120. Platform Snapshot
Lichess currently shows eight variants.
Catalog contains more.
No conflict.
121. Same Name Cross-Platform
Promotion differs.
Data import must flag mismatch.
122. Solved Claim
Antichess is solved.
Question:
- which exact rules/setup and weak/strong sense?
123. Tier A
Deep coverage.
Not:
best variant.
124. Tier C
Short reference entry.
Can still be historically important.
125. New Variant
Fits Ruleset Profile.
No architecture change needed.
126. Modern Inventor Claim
Source original publication.
127. Historical Origin
Use consensus/hypothesis.
No invented founder.
128. Freestyle Trademark/Event
Brand metadata.
Rules:
- Chess960.
129. Pre-Game Randomness
Chess960 start selected.
Then deterministic moves.
130. In-Game Randomness
Dice determines allowed piece.
Different design property.
131. Symmetric Yet Biased
Same armies. First move advantage exists.
132. Asymmetric Yet Balanced
Different armies/objectives can compensate.
133. Dominant Strategy
Variant repeatedly collapses to one exploit.
Design audit signal.
134. Raw Export Preserved
Future parser discovers missing custom field.
Data recoverable.
135. Normalized Only
Unknown platform field discarded.
State irrecoverable.
136. Round Trip PASS
Import/export keeps:
- legal moves;
- pockets;
- rights;
- counters;
- teams.
137. Round Trip Visual PASS but Semantic FAIL
Board image same. Pocket lost.
Not interoperable.
138. Competition Format Boundary
Chess960 tournament appeal:
- competition procedure.
Chess960 castling legality:
- variant ruleset/profile.
139. Historical Relationship Boundary
History of shatranj:
- historical evidence/reconstruction.
Chosen playable reconstruction:
- variant ruleset/profile.
140. Composition Boundary
Circe composition:
- fairy-composition context.
Circe as repeatable playable ruleset:
- a playable variant profile if the game is cataloged.
141. Notation & Data Boundary
PGN/FEN base syntax:
- standard notation/data rules.
Crazyhouse/Chess960 extensions:
- variant ruleset/profile.
142. Complete Variant Analysis
Ruleset → rule delta → legality → strategy → data → implementation → provenance.
143. Complete Variant-Literacy Pass
The variant-library pass is complete.
Next:
- cross-domain English audit;
- duplication/gap/source QA;
- refinement.
Not:
- automatic expansion before audit.
A variant is understood when you can reproduce its legal state and predict which orthodox assumptions stop being true.
Turn the 143 Patterns Into Active Training
Do not read the list as trivia. For every pattern, answer four prompts:
- classification — ruleset, mode, format, implementation or historical relative?
- defining rule — what exact condition makes the label correct?
- strategic consequence — what familiar heuristic changes?
- state/data consequence — what extra information must be recorded?
Then create a counterexample by changing one condition. A random back rank that violates bishop-color or king-between-rooks constraints is not Chess960. A player who cannot see a board but receives every move is not playing hidden-information chess. A FEN that recreates the board but loses a pocket can be visually correct and semantically wrong.
Build Cross-Family Comparisons
The most valuable comparisons cross category boundaries:
- Crazyhouse drops vs shogi drops;
- blindfold vs Kriegspiel;
- Chess960 pre-game randomness vs in-game randomness;
- four-player single-board teams vs bughouse coupled boards;
- Antichess mandatory capture vs ordinary sacrificial play;
- Atomic blast protection vs orthodox defended pieces;
- regional chess-family game vs modern designed variant;
- engine support vs authoritative rule definition.
These comparisons reveal the structure of variant chess more reliably than memorizing another hundred names.