Recognizing Known Positions

Earlier this month at a youth tournament that I ran, I watched one of my students miss an elementary checkmate in two moves. It was a ladder mate (or rolling barrier, as it is called in Bruce Pandolfini, Pandolfini's Endgame Course [1988]). But, a few moved later, this same player executed the checkmate. When he was successful, he controlled the first and second rank. He missed it when the mate could have occurred on the h-file with the g-file also under control.

I suspect that known patterns may be harder for young students to recognize when they are rotated 90°.

Last night, I reached a position where I had to execute a checkmate with knight and bishop. It was the first time that I had such a position that was not due to seeking it, such as when I underpromote a pawn. After I captured my opponent's last piece, I had very nearly the position that I have used in training. The checkmate took me 32 moves, but there were a couple of times when my move extended the distance to mate by six. My opponent answered these with moves that helped me get back on course.

Black to move

I played 107...Nd6, one of two optimal moves.

After 108.Ka5, Kc6 would have kept me on a known path, but I played 108...Bc5, which is equally good in terms of distance to mate. The move I played shows that I was not recognizing the pattern.

Several moves later, White's king has ventured into territory that I might have controlled.

Black to move

116...Nc3+ extends the distance to mate by one move.

Had I played 116...Be3, forcing White's king to the edge, I would have been following advice I've given students dozens of times, usually while teaching two bishops against a lone king. Here, that is the best move. Then again:

Black to move

I was feeling confused when I missed the mate in eleven that forces in three moves a position that I know.

118...Bc3 119.Kb3 Kd3 120.Ka4 Kc4 121.Ka3

Black to move

121...Bb4+ forcing White to the second rank when 122.Kb2 Ne3 sets up the barrier that I studied in Pandolfini's Endgame Course the first time that I learned this elementary checkmate.

White to move

Alas, I made a knight move and it was still mate in 18, as it had been since my move 116.

Nonetheless, I finally reached a position where I was able to draw on memory and calculation only two to three moves deep to finish the job.

Black to move, mate in nine

My work studying Thomas Engqvist, 300 Most Important Chess Positions (2018) resumes today with this position from Timman,J. -- Lutz,C., Wijk aan Zee 1995.

Black to move

Here, Black must defend successfully, avoiding the position analyzed by François-André Danican Philidor in 1849, which I spent some time working on Friday, and between rounds in a Swiss tournament this past weekend. It was the previous position in Engqvist's excellent book.

The 90° rotation might vex me the same way it did my young student.