One thing I always wondered is how many moves, on average, do you have to play before reaching a position that has never before seen on Earth?

Or maybe the question should be what percent of games reach a position that has never before been seen?

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recursivecaveat 9 hours ago | parent | next [-]

Apparently ~75% of the positions in the lichess database (as of 6 years ago) have only been seen once ever. Average game length is 30-40 moves, so for the completely average player it would be like 10+ moves I suppose. The stronger the players the longer it will take: I found some comments suggesting 20+ for high level players.

	▲	empiko 2 hours ago \| parent [-]
		I don't think the math is correct here. The 25% of positions that have been seen more than once represent more than 25% of the occurrences. Even if all of them would be seen only twice, you should already see them in 40% occurences.

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tromp 10 hours ago | parent | prev | next [-]

I think that the average chess game played between humans contributes between 20 and 40 new positions (note that a 30 move chess games has 60 plies).

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bdamm 10 hours ago | parent | prev [-]

You'd probably need to make a determination of the skill of the players. A very strong player vs a novice could be scholar's mate most of the time.

	▲	dpc050505 9 hours ago \| parent \| next [-]
		A very strong player would show the novice the scholar's mate once and then move on to hanging tactics and pieces on purpose so that the novice starts seeing things, probably leading to positions that are a lot more rare.
	▲	reassess_blind 10 hours ago \| parent \| prev [-]
		Yes, the stronger the players, the more often they will both go deeper into established theoretical lines that have been played before.