11世紀ヨーロッパで生まれた「哲学者のゲーム」。チェスと違い、駒の価値は数そのもの — 円（対角に1マス）・三角（縦横2マス、または桂馬状の跳躍）・四角（縦横3マス、またはより長い桂馬状の跳躍）・ピラミッド（内部に残っている円・三角・四角の動きをすべて使える積み駒）。捕獲方法は4種類：①同値の相手駒へ移動する「会敵」、②自分の駒の数値×距離が相手駒の数値と等しくなる「侵食」、③盤上の既存の味方駒と今動かした駒の数値を四則演算した結果が、両者に挟まれた敵駒の数値と一致する「待ち伏せ」、④敵駒の四方（または斜め四方）をすべて自軍の駒または盤端で囲む「包囲」。勝利条件は史料通りの「デ・コルポレ」——対局前に目標の捕獲数を決めておき、先に到達した側の勝ち（対局設定で選択可、無効化して全滅制にすることもできる）。歴史的な「栄光の勝利」（相手のピラミッドを崩した上で、相手陣内に算術・幾何・調和数列を並べる）は非常に複雑なため、このバージョンでは実装していない。
The "Philosophers' Game," born in 11th-century Europe. Unlike chess, a piece's power lies purely in its number. Rounds move one square diagonally; Triangles move exactly two squares orthogonally or diagonally, or make a knight-shaped leap; Squares move exactly three squares, or a longer knight-shaped leap; Pyramids are stacks that can move using any movement type still present among their remaining internal layers. There are four ways to capture: Meeting (moving onto an enemy piece of equal value), Eruption (your piece's value times the distance to an enemy piece equals that enemy's value), Ambush (the moved piece and an already-positioned friendly piece flank an enemy piece such that some combination of their two values — sum, difference, product, or quotient — equals it), and Siege (an enemy piece fully surrounded on all four orthogonal or all four diagonal sides by your pieces or the board edge). Victory follows the historical "De Corpore" rule as written — the two players agree beforehand on a target number of captures, and whoever reaches it first wins (set the target in Game Setup, or turn it off for annihilation-only play). The historical "Glorious Victories" — arranging arithmetic, geometric, or harmonic progressions on the opponent's side of the board after destroying their Pyramid — are considerably more intricate and aren't implemented in this version.
| 駒 | 動き |
|---|---|
| 円 (Round) | 斜め1マス |
| 三角 (Triangle) | 縦横2マス、または桂馬跳躍 |
| 四角 (Square) | 縦横3マス、または長い桂馬跳躍 |
| ピラミッド (Pyramid) | 内部に残る駒種の動きをすべて使用可 |
| Piece | Movement |
|---|---|
| Round | 1 square diagonally |
| Triangle | 2 squares orthogonally, or a knight's leap |
| Square | 3 squares orthogonally, or a longer knight's leap |
| Pyramid | Any movement type still present in its remaining layers |