High Chess

High Chess is a drawless variant that gives Black compensation for White’s first move.

Games that would be drawn are instead won by the player whose King is closer to the centre of the board, or by Black if both Kings are equidistant from the centre. Players may pass rather than move, but all other rules are the same as Orthodox Chess.

Rules

The player whose King is closest to the centre of the board is called High, and their opponent is called Low. The distance is the number of steps, ranging from zero to three, that the King would need to move to one of the central four squares on the board (if it were empty). Black is deemed to have a height advantage, so if both Kings are equidistant from the centre, Black is High and White is Low.

A player’s move is called vital if it irreversibly changes the game, such as by capturing or moving a pawn†. Passing is a non-vital move.

Each player begins with 50 vitality, and at the end of each player’s turn:

• If their move was vital, their vitality is reset to 50.

• If their move was non-vital and they are Low, they lose one vitality.

• If they have zero vitality and have not checkmated their opponent, they lose the game by exhaustion.

The Low player loses the game when they exhaust all of their vitality, which is analogous to the fifty-move counter in Orthodox Chess. In practice, the Low player should resign when the game is continuing indefinitely, so there is no need to keep track of vitality: in the rare event that it is required, it can be determined by examining the game’s history.

Note that the High player will not always have a vitality of 50, as becoming High with a non-vital move does not revitalise the player.

Notes

Effects on gameplay

Highness removes all draws. Games that would be drawn due to the fifty-move rule or three-fold repetition in Orthodox Chess are won by exhaustion in High Chess. Stalemate is removed as movement is optional, but a player that would be stalemated in Orthodox Chess will be forced to pass in High Chess, and will usually lose either by checkmate or exhaustion. Games that would be drawn due to insufficient material in Orthodox Chess are usually won by whoever gets their King to the centre of the board. There are no draws by mutual agreement (outside of casual play).

Highness significantly changes the endgame. When there are few men left on the board, Kings will gravitate towards the centre. While checkmate is still a common outcome, endgames such as King + Bishop + Knight vs King are easier to win by exhaustion.

Highness puts the onus on the Low player to do something. If they only make non-vital moves they will lose by exhaustion, so they are compelled to make vital moves, become High, or checkmate their opponent. While they may pass rather than move, the Low player will be exhausted if both players repeatedly do so. Therefore, passing is only useful to the High player, and only the Low player can find themselves in zugzwang (the situation in which all of one’s available moves are detrimental).

Rationale

High Chess addresses two issues in Orthodox Chess: the prevalence of draws and White’s first-move advantage. Neither of these are major problems for most players, but at elite levels most games are drawn, and more than 60% of decisive games are won by White.

Many players prefer the possibility of draws, but there are few options available for those wanting a drawless alternative. In King of the Hill, which inspired High Chess, players win by moving their King into one of the central four squares. This eliminates most draws, but fundamentally changes the opening and middlegame. In contrast, the major differences between High Chess and Orthodox Chess are in the endgame, particularly in games which would have been drawn in Orthodox Chess. Armageddon is a variant in which draws count as wins for Black, and White is given extra time as compensation. This approach requires that chess be played quickly, as does Rustan Kasimdzhanov’s proposal that drawn games be replayed with colours switched and shorter time controls. High Chess, however, can be played with classic time controls, or even without a clock.

Black’s height advantage, which makes Black High when both Kings are equidistant from the centre, has been designed to balance White’s first-move advantage. My hope is that the win ratio between White and Black will be more equal than it is in decisive games of Orthodox Chess, although in both games the ratio will depend on whether the players are novices, grandmasters, or computers. When it is played by two perfect players only one of them will have a winning strategy, but determining which is not computationally feasible.

High Chess was originally published here on Reddit. Some minor edits have been made, such as the change from momentum to vitality.

†Vital moves are those that are irreversible, which includes some that do not reset the counter for the fifty-move rule in Orthodox Chess, such as castling and the movement of rooks that had the potential to castle. This distinction was made to ease analysis of the game, such as the creation of endgame tablebases. There are, however, some edge-cases: a player who has the option to capture en passant always makes a vital move whether they capture en passant or not, since the game can never return to a point where they can make that same capture. It is not obvious whether the option to capture en passant should be recognised if there is no pawn available to capture, or if the only pawn available is pinned. I am inclined to dictate the following, but could be persuaded otherwise: a move is vital if (1) a capture is made, (2), a pawn is moved, (3), a King is moved for the first time (and a Rook that it is paired with is yet to move), (4) a Rook (that was present at the start of the game) is moved for the first time (and the King it is paired with is yet to move), or (5) any move is made while the player has a pawn that is able to capture en passant, even if that pawn is pinned.

Last revised by Grant Sinclair.