Speaking about chess often means speaking about its rules. Some move their pieces on a square board, others on a grid cleaved by a river; some games allow captured pieces to return to hand, elsewhere they transform by promotion. Yet these divergences are only the surface of a shared depth.

To the hurried eye, everything seems mechanical: board size, lines of force, conditions of capture or return. But these technical choices mostly sketch an attitude toward play: a preference for grip or for momentum, for closure or for circulation, for material economy or for positional plasticity.

In certain historical forms, the game continued to the effective capture of the king—the terminal piece. Resignation offered an earlier exit, but the terminal criterion remained concrete: remove the piece that conditions the continuity of play. In others, the game stops at the recognition of inevitability: the king is in check with no escape—one stops at mate without demanding the act.

A symmetric doorway leads to the same verdict: stalemate aligned toward self-check. The king is not in check, yet every legally available move would place him there. Again, whatever the next move, capture is guaranteed by the structure of the position; the difference between stopping and carrying out the capture belongs to implementation.

Why then forbid self-check? It is a design choice: if such a move condemns, the position already punishes the absurd. One may prefer to preserve the freedom to condemn oneself—or to bound it by convention. Neither alters the inner logic.

These apparent divergences are easily explained: they reflect historical and sociocultural biases. The game of chess—whether Western, Japanese, or Chinese—remains one in principle; what varies is style, and style is the way a single idea finds its face in the world.