|David2009: After move 83 P Mahesh Chandran vs Z Izoria, 2007 with Black to play is as below.
The Nalimov database http://www.lokasoft.nl/tbweb.htm tells us there is a mate in 23. It is interesting to work out how to mate from the diagram.
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To checkmate, Black needs to drive White into the a1 corner. With White to move in the diagram, 1. Ka3 Nd1 2. Ka4 Ng2+ does the trick. So Black needs to lose a move, which can only be done with his K. But at the moment the K is needed to guard b5 (for example 83... Kc3?? is an immediate draw after 84 Kb5). So the FIRST STAGE is to reposition the N at d4 in the diagram (to guard b5). Thus 83.. Nf5 84. Ka3 Kc3! 85. Ka4 Nd4 86. Ka3
The NEXT STAGE is to triangulate with the BK. 86... Kc2 87 Ka4 Kd3 88. Ka3 Kc3 89. Ka4 Kc4 90. Ka3
The FINAL STAGE is to mate. Care is still needed e.g. 90... Nf5 allows the WK to escape. So 90... Ne2! There is still fight in White's position: 91. Kb2 Kd3 92. Kb3 Nc1+ 93. Kb2 Kd2 94. Ka3 Kc4 95. Ka3 Nd3 96. Ka4 and we are back more or less in the diagram position but with the free N at d3 and not at e3. This tiny change makes the mate possible.
When I first started writing this kibitz, I thought it was possible to force the diagram position with White to move when the win would be straightforward (mate in 10 with a simple main line). But there was a massive hole in my intended line which would have let White escape. Moral - NN vs P is not easy even when the King appears already confined.