Misère and mandatory-capture games invert some of orthodox chess's deepest assumptions. Material can become a liability, mobility can be undesirable and a legal capture can be compulsory.
Because names such as Antichess, Losing, Giveaway and Suicide are used inconsistently across communities, this domain treats them as a family plus an implementation profile.
Misère Objective
A misère objective rewards achieving what orthodox chess normally avoids—commonly losing all one's pieces or having no legal move.
Lose All Pieces
In many Antichess profiles, a player wins by getting rid of every piece.
Stalemate-as-Win Variants
Some losing-chess implementations also award victory to a player with no legal move. This rule must be explicit because not every related variant treats stalemate identically.
Mandatory Capture
If at least one legal capture exists under a mandatory-capture ruleset, a non-capturing move is illegal.
Antichess
In the current Lichess Antichess profile the king is non-royal, check is irrelevant, castling is absent, captures are compulsory, pawns may promote to a king, and a player wins by losing all pieces or being stalemated.
Losing Chess
Losing Chess is a family/name whose exact king, stalemate and promotion rules vary across authorities. Never assume it is identical to one platform's Antichess.
Giveaway Chess
Giveaway Chess is another common misère/mandatory-capture label. It may be synonymous locally with Antichess or may use a different royal-king/stalemate profile.
Suicide Chess
Suicide Chess is a historically/common alias in some communities, but platform conventions vary. Store it as an alias only after matching the exact rules.
Names Are Not Universally Synonymous
Antichess/Losing/Giveaway/Suicide are not guaranteed synonyms. Canonical identification requires the ruleset profile, not the displayed name.
Royal vs Non-Royal King
The king can be royal in some losing variants and non-royal in others. This single choice changes check, capture, castling and legal-move generation.
Check Exists / Does Not Exist
If the king is non-royal, check has no special legality meaning; if royal, ordinary king-exposure restrictions can remain.
Castling
Under misère/mandatory-capture rules, Castling must be derived after checking the implementation's king, compulsory-capture, stalemate, promotion and castling settings. Orthodox evaluation is not the default.
Mandatory Capture
If at least one legal capture exists under a mandatory-capture ruleset, a non-capturing move is illegal.
Choice Among Captures
In the Lichess Antichess profile, capture is compulsory but when several captures exist the player may choose among them.
En-Passant Capture
If en passant is a legal capture under the chosen implementation and captures are compulsory, it participates in the compulsory-capture set. Profile the rule explicitly.
Promotion
Promotion options vary across misère games. Current Lichess Antichess even permits promotion to a king because kinghood is non-royal.
Stalemate
Under misère/mandatory-capture rules, Stalemate must be derived after checking the implementation's king, compulsory-capture, stalemate, promotion and castling settings. Orthodox evaluation is not the default.
Win Condition
Under misère/mandatory-capture rules, Win Condition must be derived after checking the implementation's king, compulsory-capture, stalemate, promotion and castling settings. Orthodox evaluation is not the default.
Non-Royal King
A non-royal king can move into attacked squares and be captured like another piece, subject to the variant's ordinary movement/capture rules.
No Check Constraint
With a non-royal king, moves are not illegal merely because they expose the king; there is no ordinary check/checkmate constraint.
No Castling
Current Lichess Antichess has no castling.
Compulsory Capture
Every move-generation step begins by checking whether at least one capture exists. Quiet moves are considered only when no capture is available.
Lose Pieces / Stalemate to Win
Current Lichess awards victory for losing all pieces or reaching stalemate/no legal moves.
Promotion to King
Current Lichess allows a pawn to promote to a king, illustrating why promotion menus are implementation state rather than universal chess ontology.
Material as Liability
Material can be a burden because every remaining piece is something the player may still need to dispose of.
Forced-Capture Control
The key tactical resource is often forcing the opponent to take a particular unit or sequence of units.
Tempo
Tempo remains move-order currency but its value can change radically in races, forced-capture games, waiting strategies or Bughouse clock coupling.
Sacrificial Routing
Under misère/mandatory-capture rules, Sacrificial Routing must be derived after checking the implementation's king, compulsory-capture, stalemate, promotion and castling settings. Orthodox evaluation is not the default.
Mobility Can Be Bad
Extra mobility can prevent a desired stalemate and give the opponent more ways to avoid taking your material.
Endgame Inversion
A side with one awkward piece can be closer to victory than a side with many pieces; orthodox material/endgame heuristics invert.
Orthodox Heuristics That Fail
Win material, protect the king, avoid hanging pieces and maximize mobility can all be wrong under misère rules. Derive evaluation from the actual win condition.
Antichess-Family Practice Set
A strong understanding includes checking compulsory captures first, profiling king/check/stalemate/promotion rules, reasoning about sacrificial routing and rejecting orthodox material heuristics.
Mandatory Capture Creates a Different Search Tree
In orthodox chess, captures are candidate moves. In mandatory-capture chess, the existence of a capture can delete every quiet move from the legal set. Strategy therefore revolves around controlling which captures become compulsory.
A hanging piece can be a forcing device. You may offer material not because the opponent wants it, but because the rules compel a capture that moves their piece onto a bad square or opens your own disposal route.
Material, Mobility and Tempo Can Reverse Sign
More pieces can be worse because you still have more material to eliminate. Mobility can be bad if it creates unwanted captures. Promotion can be strategically awkward if it creates a harder-to-dispose piece. A king may be ordinary capturable material rather than a royal unit.
Do not merely invert orthodox piece values. The value of a unit depends on how easily it can be forced onto capture routes and how much control it gives over the compulsory-move graph.
Name the Exact Profile
When comparing Antichess, Giveaway, Losing Chess or Suicide Chess, build an implementation table for king status, check, castling, en passant, stalemate, promotion and winning condition. These names have historically overlapped without defining one universal ruleset.