On Monday I left you with this position, which was agreed drawn in the game Bogoljubov – Thomas, played at Hastings on 13 September 1922.

White could have won by marching his king to b2 to pick up the black pawn, and then back to c8 to set up the Lucena Position.

You do know all about the Lucena Position, don’t you? If not, you really should!

For example, 79. Kd5 Ra5+ 80. Kc4 Ra4+ 81. Kb3 Ra3+ 82. Kc2 Rc3+ 83. Kb2 a1Q+ 84. Kxa1 Rc2 85. Kb1 Rc3 86. Kb2 Rc4 87. Kb3 Rc1 88. Kb4 Rb1+ 89. Kc5 Rc1+ 90. Kb6 Rb1+ 91. Ka7 Rc1 92. Kb7 Rb1+ 93. Kc8 Rb4 94. Rh3 Rb2 95. Re3+ Kf7 96. Re4 Kf6 97. Kd7 Rd2+ 98. Kc6 Rc2+ 99. Kd6 Rd2+ 100. Kc5 Rc2+ 101. Rc4 and wins.

This is basic endgame knowledge for any serious competitive player now, but, 100 years ago, even the world’s strongest players didn’t always get it right.

Congratulations to David Maycock Bates and anyone else who solved it correctly.