Changes

A [[Distance|Chebyshev Distancedistance]] of at least four to the [[Promotion Square|promotion square]] with a [[Manhattan-Distance|Manhattan distance]] less than eight for the attacking king is necessary to win that game (<span style="background-color: #c0ffc0;">green area below</span>).While implementing this pattern inside a However, there are positions where the attacking king may reduce the distance due to [[Interior Node RecognizerDiscovered Check|interior node recognizerdiscovered check]], one has to take care that with the king in the corner (i.e. black king on a1), the queen has no mate in one (i.e. on c1).

{|| <fentt border="double" style="font-size:24pt">...Q..../......../......../(....)K.../(.....).../(.....).../(pk...).../([k]k...)...</fentt>| <fentt border="double" style="font-size:24pt">.......Q/......../......../(....)K.../(.....).../(.....).../(pk...).../(kkk....)...</fentt>|-| Draw, &#172;([[King|&#9818;]][[Squares|a1]] &and; [[Queen|&#9813;]][[Square Control|&#10503;]][[Squares|c1]])| Win due to [[Discovered Check|discovered check]]|}

A similar draw motive occurs here with [[stalemateStalemate|stalemate]] after the queen captured the bishop pawn. The <span style="background-color: #c0ffc0;">winning area </span> of the attacking king requires a bit more calculationis depending whether the defending king resides on the [[Pawn Spans|lee-side]] or [[Pawn Spans|luff-side]] . Critical squares for <span id="Lee"></span>==Lee case==The defending king on the [[DistancePawn Spans|lee-side]] is able to threaten [[Stalemate|Chebyshev Distancestalemate]] in the corner. Critical squares are the neighbouring square on the same rank on the [[Pawn Spans|luff-side ]] (i.e. for black pawn on c2, [[Distance|&#977;(&#9812;,d2)]]),and the diagonal neighbouring square on the lee-side one rank back (i.e. for black pawn on c2, b3). Only if the attacking king can reach these squares in one move, it can assist in a [[Checkmate|checkmate]] with the queen - otherwise it is a draw - except the rare cases the attacking king may reduce the [[Distance|&#977;(&#9812;Chebyshev distance]] accordantly,b3)giving [[Discovered Check|discovered check]]). <ref>Lee-case implemented as [[Interior Node Recognizer]] implemented in [[IsiChess]]</ref>* With a <span style="background-color: #c0ffc0;">distance below two</span> to any of these critical squares, the game is won. * A <span style="background-color: #cc80cc;">distance of two</span> to any of these critical squares is not sufficient, if the defending king occupies the corner square (i.e. a1), or the 7th/8th (1st/2nd) rank on the neighbouring knight file (i.e. b1, b2).* A distance of two is required to win the game otherwise

==Luff case==When the defending king supports its pawn from the "wrong" [[Pawn Spans|luff-side]], including occupying its [[Promotion Square|promotion square]], the <span style="background-color: #c0ffc0;">winning area</span> for the attacking king is enlarged by at least one move, in luff-direction even two moves.The critical luff-side square is now one file farther away (i.e. for black pawn on c2, e2), and one critical square needs to be reached in two moves now, to either transpose to a winning [[#Lee|lee-side case]], or to assist in a checkmate on the luff-side. {|| <fentt border="double" style="font-size:24pt">......../......../..Q...../(....)..K./(.......)./(.+.....)./(..pk+..)./(..kk...).</fentt>| <fentt border="double" style="font-size:24pt">......../......../{....}...Q/(....)..K./(.......){./(.+....}.)./(..pk+..)./(.......).</fentt>| <fentt border="double" style="font-size:24pt">......../......../.......Q/(....){.}.K./(.......)./(.kp+.....){.}/(..p.+..)./kk(..k..){.}.).</fentt>|-| Draw| Win due to [[Discovered Check|discovered check]]| Draw since check parried by [[#Lee|Kb1/b2]]|}