It’s a chess move you don’t hear of very often. It’s not as popular as that thing you do with the little castles.

“En pbumant (from French: “in pbuming”Log in to see images! is a move in the board game of chess. En pbumant is a special capture made immediately after a player moves a pawn two squares forward from its starting position, and an opposing pawn could have captured it if it had only moved one square forward. In this situation, the opposing pawn may, on the immediately subsequent move, capture the pawn as if taking it “as it pbumes” through the first square; the resulting position would then be the same as if the pawn had only moved one square forward and the opposing pawn had captured normally. The En pbumant capture must be done on the very next turn, or the right to do so is lost.[1]

Such a move is the only occasion in chess in which a piece captures but does not move to the square of the captured piece. When claiming a draw by threefold repetition, two positions whose pieces are all on the same squares, with the same player to move, are considered different if there was an opportunity to make an en pbumant capture in the first position, because that opportunity by definition no longer exists the second time the same configuration of pieces occurs.

In either algebraic or descriptive chess notation, en pbumant captures are sometimes denoted by “e.p.” or similar, but such notation is not required. In algebraic notation, the move is written as if the captured pawn just advanced only one square, e.g, exf6 (or exf6 e.p.) in the illustration below.”