www.lesswrong.com/posts/inDSFwaBmZiyixufo/rational-chess

In standard chess rulesets and tournament regulations that use Armageddon as a tiebreak, the key idea is draw odds: if the game is drawn, Black wins.

The post’s parenthetical definition—“if neither player can checkmate the other”—is a different (and much less well-defined) condition. It suggests the win is determined by whether checkmate is possible rather than by the actual game result (win/loss/draw). In real Armageddon regulations, there is no requirement to prove that neither side could checkmate; instead, the arbiter simply uses the game’s outcome, treating any draw result as a Black win.

Concrete contradiction: FIDE regulations explicitly state that a draw in the Armageddon game results in Black winning. That directly conflicts with the post’s definition based on “neither player can checkmate the other.”

This sentence gives a rule definition of Armageddon that does not match how Armageddon is specified in actual competition regulations.

Under Armageddon tiebreak rules, the decisive property is the result: if the game ends in a draw, Black wins. The rule is not contingent on proving that neither player could checkmate; it’s simply “draw = Black wins.”

FIDE’s published regulations for an event that uses Armageddon state exactly this (draw → Black wins), contradicting the post’s “neither player can checkmate” definition.