Rule question: Knocked down piece in Blitz

Hi, I was wondering if a player can claim a win in the following scenario:

It is a blitz game. Player A moves and accidently knocks down a piece while doing that. Then he/she hits the clock, then he/she adjusts the knocked down piece on the opponent's time. For example like in this video around 1:08 https://www.youtube.com/watch?v=5yrn5E_MquQ

What is the proper reaction of player B?

Can he/she stop the clock and claim a win because of an illegal move? I remember seeing GM Kosteniuk doing this once.

Or should he/she just ignore it? Or rather press the clock back and say something like "Adjust on your time"?

Pieces must be fixed on your own time. I would have to look up the specifics for the exact regulations.

Thanks for your answer. It would interesting to know if that would be a sufficient reason to win/lose a game though ...

Yes it is.

An illegal move is completed once the opponent’s clock has been started. The opponent is entitled to claim a win before he has made his own move.

If you hit the clock without moving anything, then this is an illegal move (actually non-move), and the opponent could (and should) claim the win.

Cool. Thanks pfren!

Well, that's not exactly correct.  Your example doesn't constitute an illegal move.

In your example the player completed a LEGAL move and knocked over another piece and incorrectly adjusted that in the opponents time.

What you could do in tournament play is protest to the arbiter who would most likely give your opponent a warning, a time penalty if it happened again and a loss if he keeps doing it.

The example in the video is somewhere in between because the player did  let go of the bishop on the legal a8-square.

No arbiter would declare a loss here. A severe warning? Yes, most likely.

The discussion is about blitz, not regular time controls. FIDE rapidplay rules, also applicable on blitz, are like this:

An illegal move is completed once the player has pressed his clock. If the arbiter observes this he shall declare the game lost by the player, provided the opponent has not made his next move. If the arbiter does not intervene, the opponent is entitled to claim a win, provided the opponent has not made his next move. However, the game is drawn if the position is such that the opponent cannot checkmate the player’s king by any possible series of legal moves. If the opponent does not claim and the arbiter does not intervene, the illegal move shall stand and the game shall continue. Once the opponent has made his next move, an illegal move cannot be corrected unless this is agreed by the players without intervention of the arbiter.

In regular time controls one must make TWO illegal moves to lose the game- the first one does have a penalty, but does not result in game loss.

Nope, beside the point I was making.

I know it is about blitz. The question is: what exactly constitutes an illegal move?

For instance. Playing the legal move Bc4-b5 while at the same time knocking over your rook on h1 with your right elbow and pressing the clock is clearly not an illegal move.

It's a matter of gradation which surely is up to the arbiter to decide.

Some cases are clear-cut. Others are not.

Interesting discussion.

I just found the video where Kosteniuk wins the game because her opponent knocks down a piece. https://www.youtube.com/watch?v=TT5uCWXX5xc at 8:50

She says in the video that here "an interesting rule was used" which to me indicates that it was a rule for this tournament.

I looked at the FIDE rules. Normal as well as blitz. And it simply doesn't say anywhere that knocking over a piece loses the game. It's possible I missed it. But I don't think so.

" She says in the video that here "an interesting rule was used" which to me indicates that it was a rule for this tournament."

You're right. I missed this part.

Talking about rules..... My latest (second ) video...

Interesting discussion. If its not a loss, maybe it should be. Or at least penalised. I play a lot of blitz in parks and cafes and I know certain players who do this a lot who I suspect are doing it deliberately to waste time off my clock where I can't properly evaluate the position while my clock is going because his knocked over pieces are still rolling around and his hands are over the board picking them up. One player actually did this and then admitted after the game that he'd reset the pieces incorrectly. The misplaced piece being Knight which forked my Queen the next move. I hadn't claimed the win so he said too late, too bad! The Washington square chess hustlers love this kind of sleight of hand and distraction, disruption tactic. In the recent video where gm Maurice Ashley plays there, a hustler knocks over pieces on purpose during a recapture while palming an extra minor piece off the board. Of course Maurice immediately notices the missing piece and calls him out.

I saw that video too. Great trick! :-)

I like how Naka shakes his head to the beat on 1:17.

Not true. I've dealt with lots of touch-move claims as a TD and accidentally bumping/moving a piece is never considered a move.

Where I come from, your car keys are taken. If your clumsy behavior continues, you must provide a lady for a date within 24 hrs. Simple as that.