I recently had a question inspired by this game, which thankfully just ended so I can ask now: http://www.chess.com/echess/game?id=86490964

Here's the set-up to my question: I'm playing black. At move 21, I sacrifice the exchange in order to open up against white's king. I'm able to get another knight out of this, but in return white gets passed pawns on c4, d5, and d6 (in total, I have N+B vs his R+2p). And all his major pieces are still on the board, ready to usher those pawns down the board.

So I start to feel like I'm losing. Therefore, I take more time for each of my moves around here, often taking the full 3 days. White then blunders and lets me back into the game (with 35. c6), but I'm still playing cautiously and taking my time. We then reach the following position after 39. d7:


Black to play.

My move is going to be 39...Bg4, which secures the draw by perpetual check/repeating the position (as actually happened in the game). But there is a little trap in this in that I allow black to queen, but then I get mate out of it: 39...Bg4 40. d8=Q Qa2+ and mates. I doubt white will fall for this, but since ...Bg4 is my best move anyway, I can play it and hope he blunders again.

So, when do I play my move to best increase the chances that white falls for the trap? Do I play right away, so he thinks I didn't analyze enough and just blundered, or would that make it seem like I was prepared for this? Do I wait the 3 days like I have been doing so that nothing seems suspicious, or would he think that if I took 3 days I must be setting a trap if I let him queen? Again, I don't think it's likely he plays 40. d8=Q, but I'm curious to know if anyone thinks I can make it more likely that he does by either playing quickly or slowly.

Play 39...Bg4 very quickly and then type "ARGHGHH!!! " in chat.

I think waiting a few days could increase his blunder rate by ~0.05% or so. Playing 39. d7 is a tacit vote of confidence for the harmlessness of the follow-up ...Qa2+, which is an indication that he knows ...Qa2+ exists and is among your candidate moves. Waiting a few days should marginally increase the odds that an unexpected event happens in his life--one that might make him forget all about ...Qa2+ or not update on its threat level.

If White were significantly weaker, <1,200 elo or so, I'd suggest the opposite course of action: play Bg4 as quickly as possible.

Play it fast especially if he doesn't have any time on his clock

We each had 3 days per move.

I would take 2 days. It might stand-out in his mind that you didn't take the full amount of time and it might give him more confidence, but still enough time that it's believable. Disclaimer: I'm a poker player and not a chess player.

That changes things. Hard to say. I never noticed timing tells in CC unless we are both online at the same time.

What are timing tells as to conditional moves? They're different from fast moves in that they're usually well thought out despite being instant (and actually I've heard that there's a special message telling the opponent that the move is conditional, though I've never experienced it myself; or is it only when the opponent has no other ready games, i.e. the game vs me remains the only in his queue?).

E.g. when I'm going to make a trapping or complicating move that doesn't pose direct threats and looks like hanging a piece newly challenged by a pawn (which is definitely not 'overlooked' because the move is conditional), wins in naive lines but leads to drawn or unclear positions against hidden best responses, and my opponent has a different schedule and is going to make his move while I'm sleeping, should I set a conditional move up to either make him think it's an autopilot blunder (which is unlikely to work) or convey high confidence and intimidate him to the extent of fatalism and overlooking the best response, or should I intentionally make the move 'manually' next 'morning', when it's highly probable that several hours of what might look like a 'deep thought' will have passed?

Fwiw, my time per move stat is 2.5 hours, and I often blitz moves out when the opponent is also online and doesn't have a long queue of ready games. I'm afraid I give away massive timing tells by hesitating for over a day; thankfully, I don't think opponents look up my queue regularly and notice that I'm making moves in other concurrent games fast.