{"schema":"chessgrammar_motif_entry/1","slug":"overloading","name":"Overloading","aka":null,"category":{"key":"constraint","label":"States"},"edition":{"version":"v3.0","year":"2026"},"certified":true,"canonical":"https://chessgrammar.com/motifs/tactics/overloading","tabs":{"identity":"https://chessgrammar.com/motifs/tactics/overloading#identity","structure":"https://chessgrammar.com/motifs/tactics/overloading#structure","examples":"https://chessgrammar.com/motifs/tactics/overloading#examples"},"citation":"ChessGrammar (2026). Overloading. In: ChessGrammar: A reference for chess concepts, Tactics grammar, edition v3.0. Entry cg:overloading@1. https://chessgrammar.com/motifs/tactics/overloading","variants":["king_defender","rook_defender","triple_duty"],"seeAlso":[],"definition":{"id":"cg:overloading@1","statement":"A defender is the sole guard of two of its own side's pieces, each independently attacked, so that answering one threat abandons the other.","predicate":["A defender is the only piece guarding two or more of its own side's pieces, and each of those pieces is separately attacked by the opponent.","Only real duties count toward the overload. A duty does not count if another piece already shares the defence, or if the defender itself cannot make the capture.","The two threats must come from two different enemy attackers. Each threat can be answered only by turning the defender away from the other. If a single enemy piece attacks both targets at once, capturing that one attacker settles both threats. That is a defended fork, not an overload.","The king is never counted as one of the duties an overloaded defender protects. An attack on the king is check, which must be answered immediately, so it is not a duty that can wait. The king can be the overloaded defender itself, guarding two other pieces that are each independently attacked, as in King Defender."],"diagnosis":"The nearest neighbour is the same defender guarding only one attacked piece. That is ordinary defence, not overloading. The motif needs a second, independently attacked piece behind the same sole defender. If either the second attacker or the second attacked piece is removed, the overload disappears. No sibling entry covers the remaining position, which is the negation of the motif.","maturity":{"state":"stable"},"holotype":{"fen":"8/3n2k1/3p2p1/4p1Pp/PP2P2P/2N5/1K2Bq2/8 b - - 0 33","move":"d7b6","san":"Nb6","overloaded":"c3","duties":["a4","e2"],"why":"White's knight on c3 is the sole defender of two pieces: the pawn on a4, newly attacked by the knight on b6, and the bishop on e2, attacked by the black queen on f2. If either is captured, the knight cannot recapture without abandoning the other. Before Nb6 the knight guarded only e2, so the a4 duty is new."},"nearMiss":{"fen":"8/3n2k1/3p2p1/4p1Pp/PP2P2P/2N5/1K2Bq2/R7 b - - 0 33","move":"d7b6","san":"Nb6","delta":"A white rook is added on a1, a second defender of the pawn on a4; everything else is identical.","neighbour":"none","why":"With a second defender on a4, the knight on c3 is no longer its sole guardian, so that duty no longer counts toward the overload. The knight on c3 is left with only one duty, e2, and a single duty is not an overload. This position is the negation of the motif. Sharing one of the two duties ends the whole state, and no sibling entry covers what remains."},"nearMissPending":null,"standing":{"certified":true,"scope":"definition"}},"axes":[{"key":"trigger","name":"The named quick-win fact that fires on top of the base Overloading state","values":["king_defender","queen_defender","rook_defender","triple_duty"],"nature":"facts","note":"Not a clean single-fact partition: King Defender describes the defender's own piece; Queen Defender and Rook Defender describe one of the duties instead -- a different fact entirely; Triple Duty describes a duty count. All four can fire together on the same position -- for instance, a king defending three pieces including a queen is King Defender, Queen Defender, and Triple Duty at once. See axesNote for the full picture."}],"summary":"A single defender charged with more duties than it can keep."}