the bot is not in a hurry
Levy Rozman says it all the time: chess bots have a sense of humor. They don’t just beat you. They hand back a position you’d lost, let you breathe, then take you apart slowly. Offered a quick finish or a long grind that leaves you with nothing, they pick the grind.
It looks like a cat with a mouse. It isn’t. Nothing in the bot’s arithmetic says a win now is worth more than a win later.
An engine gives a position one number. Up six now and up six thirty moves from now are the same six. AlphaZero and its open-source descendant, Leela Chess Zero, are flatter still: they learn from one signal, win, draw or loss. A mate in five and a mate in fifty both count as a win. Once a game is won, every winning move looks the same.
In August 2018 Leela had a won game against the engine Chiron at Chess.com’s headquarters. Then it sacrificed its queen. Then the second queen. It underpromoted a pawn, gave away a rook and a knight, and only then mated. The audience wondered if they’d watched a machine mock its opponent. Leela’s community called the habit trolling, and the fix tells you everything: they added a moves-left head to the network, a guess at how long the game has to run, so the search would lean toward moves that end it. They had to put the clock in by hand.
Go has the mirror image. AlphaGo closed out won games with slack moves and hair-thin margins, because, as Demis Hassabis put it, it maximizes its chance of winning, not its margin. In Go the indifference read as timid. In chess it reads as sadism. Same flat number both times. We supply the personality.
We count time because time costs us. There’s a clock, you get tired, and every extra move is one more chance to blunder. For a person a faster win is a safer win. That’s all “when you’re ahead, trade pieces” means. It’s a discount rate, and it’s there because you’re the weak link in your own winning position. The engine isn’t. Move ninety is as clean as move nine.
The only human reason to drag out a won game is to make the other person feel it. Cruelty is making someone wait. The bot isn’t making you wait. It doesn’t know waiting exists.
That outlasts chess. Every objective we hand a machine is a number, and the number holds only what we put in it. Leela got caught because people were watching. Most systems don’t play in front of an audience.
If you want a machine to care about time, you have to put the clock in yourself.
Sources: The chess player that mocked her opponent, The Wire Science ↗ · Google’s AlphaGo barely beat the top Go player because it avoids risks, VentureBeat ↗ · The new MLH settings, Next Chess Move forums ↗