What to do when your opponent announces mate in 73

Here’s a fairly amusing chess story to possibly entertain you.

Has your opponent ever announced “mate in 73”? Well, supposing they did, do you think you would reply “yes, I agree, great game, well played!”

It happened to me last month.

Of course we are talking correspondence chess here. I was playing for “Herts & Minds” (Hertfordshire) in the States and Regions Correspondence Chess Championship, Division 2. 

The event cross-table is here:


And you can replay the game here


Remember this is correspondence chess and both players are using computer engines and databases. So no blunders. But it does answer the question that a lot of people ask - how can you win/lose a correspondence game, when you have a computer engine to help you out? The answer is, basically, very long-term strategic weaknesses that the engine may evaluate as a tiny disadvantage, but the exploitation of the advantage is so far outside the engine’s horizon that it tells you that the position is “equal” or nearly so. 

However, your engine will not tell you that the final position, after 96 moves, is “mate in 73”. Because that is outside the engine’s horizon, too. 

But the International Correspondence Chess Federation uses “table bases”, for positions with up to 7 pieces on the board. In simple terms, this means that chess has been “solved” for up to 7 pieces. You can look up the best moves in a table. And the table says that, in the final position, with perfect play by both sides, it is mate in 73. Once an ICCF game gets down to 7 pieces, the players can simply pack up and go home, and record the result that the table base tells them is inevitable.

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