how can lichess ban players for having been helped by human assistance?

Something very weird happened while I was watching a game between a 1080 elo rated player and another player rated 1400: the game started by very inaccurate moves, and then the lower rated player found a brillant move for his level (move 8) maybe with a bit of luck, which was to castle to attack the king queen alignment with the rook. The game ended very quickly with an attack on the king and bad defence by the opponent. As the opponent couldn't believe he was beaten so badly by a so low rated player and saw that I was watching, he accused me in the private chat of giving advice which is cheating and probably reported. The ban occurred in the minute after.

You can analyse the game, there is no engine looking move, so probably lichess considered that I gave advice to the player. But how lichess can determine this given that I didn't write anything on the chat? Me I know that I didn't give any advice and that the lower rated player is somehow underrated, but it's impossible to prove this or the opposite. Maybe they detected that we were in the same place which is true, but what does it prove? I really don't understand how a so quick decision can be done for something so unprovable.

Do you have any clue on what could have happened? This is the game which resulted to a ban just after:

@nicolas647 said in #1:
> The ban occurred in the minute after.
>
> You can analyse the game, there is no engine looking move, so probably lichess considered that I gave advice to the player. But how lichess can determine this given that I didn't write anything on the chat? Me I know that I didn't give any advice and that the lower rated player is somehow underrated, but it's impossible to prove this or the opposite. Maybe they detected that we were in the same place which is true, but what does it prove? I really don't understand how a so quick decision can be done for something so unprovable.
>
> Do you have any clue on what could have happened? This is the game which resulted to a ban just after:

it appears you're trying to learn how to avoid cheat detection? nobody knows how cheat detection works. it's done by a blackbox the size of a loaf of bread, donated to lichess by an unknown man wearing a red glove on his right hand. The box just blinks away and bans cheaters.

@nicolas647 said in #1:
> You can analyse the game, there is no engine looking move

That's nothing but a statement of yours ... I strongly disagree already regarding the move you highlighted, 8. 0-0. Not only it is the top engine move, but it's also absolutely clandestine for me too. First, it's not a theoretical line (Na3 is already somewhat unconventional and objectively bad). There's even material but the white knight is hanging. The obvious thing to do for any normal-skilled player (like me, being ~2000) is the second-best move, Ne3, unpinning the other knight. How can you know that by 0-0 you get MORE THAN FULL COMPENSATION FOR A WHOLE MINOR PIECE??? You can't tell the guy is underrated by like 1500 points to be confident in playing 0-0 on his own. I can hardly imagine that this was above-board. Besides, who says that the ban had to be only because of this particular game? There could be others?

I definitely think Lichess detected engine cheating. If you know that you didn't have a hand in this then you can just ignore the assistance accusations (and maybe report them if you like). But it's hard to believe you saying you were in the same place watching the game live.

By the way, mods CAN and WILL check private messages if (and only if) there's a sound reason to do so.

No I do not try to avoid cheat detection as I have no intention to cheat by any way.

I highlighted 8. 0-0 because it's the only dubious move to me. I personally asked the player afterwards and he answered me that he thought that he had necessarily lost one of his knights, not seeing that one of his knight was protected, so he looked for counterplay. Me neither I would not have not have played this move, but sometimes by chance GM moves can coincide with beginner moves, just they don't do them for the same reason. Usually the ending is not the same, but in this case it was very straightforward. That's why it's difficult to judge on a single move.

@nicolas647 said in #1:
> he accused me in the private chat of giving advice which is cheating and probably reported

if lichess believed that, you would be banned too. you are not banned, so that is not what they believe.

@nicolas647 said in #4:
> No I do not try to avoid cheat detection as I have no intention to cheat by any way.
>
> I highlighted 8. 0-0 because it's the only dubious move to me. I personally asked the player afterwards and he answered me that he thought that he had necessarily lost one of his knights, not seeing that one of his knight was protected, so he looked for counterplay. Me neither I would not have not have played this move, but sometimes by chance GM moves can coincide with beginner moves, just they don't do them for the same reason. Usually the ending is not the same, but in this case it was very straightforward. That's why it's difficult to judge on a single move.

If you're a blind hen finding a grain of gold (not just corn) like 0-0, then how likely is it that you keep on finding all the other great moves? Mods and AIs take this into account. The guy can explain himself in lichess.org/appeal but I strongly doubt he can legitly do so.

By the way I saw a few other games where he spent awkwardly long times for obvious moves.

> Do you have any clue on what could have happened? This is the game which resulted to a ban just after:

@nicolas647 don't just assume that it was a ban because of cheating: it's a ToS violation there are multiple ways to violate ToS, cheating is only one of them. At the end of the day only this person knows why they got banned. If they want to get unbanned they can appeal it. Not really anything else.

As for castles, to me personally it looks more like a mistake turned brilliancy. If you don't see knight e3, which is a backwards knight move, and don't see that it solves the problem of your other knight being pinned to the king, castles is just a damage control move after "blundering one of your pieces".

@h2b2
Personally to me it's more one of those moments when you get annoyed "why did I blunder a piece" and then realise only afterwards with analysis that it was the best move - I've had a similar event happen fighting the dragon "blundering" my rook accidentally in the corner only to absolutely murder my opponent on the dark squares and finding out that sacrificing the rook was the best move in analysis.

Finally you can always ask the person to see if they want to be truthful in messages to find out what happened rather than starting up a post about a player getting banned ;)

It's true he found all the top engine moves from there, but this was only looking for check and attack the king. All of this seems very natural and can be found by a human, mostly that is what we do in puzzles. Besides this as I was there I saw that he didn't use an engine, but I don't ask you to believe me on that point.

Concerning the appeal, he already did one without giving explanations on those points, just thinking he played poorly and his opponent played even more poorly, not realising how brilliantly he played at the end of the game, and got a deny without any explanation.

> It's true he found all the top engine moves from there, but this was only looking for check and attack the king. All of this seems very natural and can be found by a human, mostly that is what we do in puzzles.

That's **your opinion.** That's not the truth in my book. For an 1100 guy it's definitely not. Why did he spent 20 seconds for Re1 which is the plainly obvious follow-up of 0-0? Of course I'm not surprised he was denied.

You say you were there live. You received accusations because you were spectating the game with your account. Why would you do that if you're already joining your friend live IRL?

I think he takes time for all of his moves because of a lack of confidence and habit as he only returned to play chess recently. He is not used to play blitz and only plays with slow time controls.

I spectated the game because he was on his phone so it was more convenient for me to watch the game on a separate screen.