A GOTCHA lesson

I lost a game because I didn't understand this GOTCHA. I thought others who are newer to the game might not know it either.

With the black Rook being pinned to the black King, I didn't worry about this double-attack on f2 because the black Rook can't move. If the Queen takes f2 ( I was chuckling to myself) then I'll just take the Queen with my King.

 What a shock that I couldn't take her! I could have Rf1 or Ne4 but I thought I was safe! So the black Rook can be used as defense even though it can't move (pinned)?! It feels INACCURATE although I'm sure it's correct. With a Knight's direction-change and leaping-pieces ability, I'll especially need to study them in these pinned situations!

Are there any other shocking or unusual behaviors we need to watch for that you might kindly share with newbies? I understand the en passant step ... any other GOTCHAS, please?

Thank you! Yes, that helps! It was simply so shocking! But it isn't the first game I lost and it won't be the last. I'll study even more and hopefully will find any other gotchas during study instead of during a game! Much appreciated!

You should also be aware that a piece that can't legally move due to being pinned to its own king, in addition to defending pieces from the king, can still check or even contribute to a mating attack. If your king was on f1, for example, Qxf2 would still be checkmate.

Some examples for visualization:

Oh this is bizarre ... "can still check or even contribute to a mating attack."

How can black Rook partake in ATTACK (which implies moving) if it can't move? It is all bluff but I guess bluff counts! This adds further depth to my understanding, thank you so much!

I've been playing against Maximum (3200) via Analysis (and then bottom bullseye 'Practice vs Computer') and I reverse which side I'm playing in the middle of the game (actually every move) so I can control all pieces but see how Maximum plays at every move as it plays both sides. The most intriguing has been this 'pinned vs bluff attack' situation using Knights!!!

Chess, this website, and the people here COMPLETELY RULE!!

I just saw your examples - THANK YOU!!!!! Such fun!

edited: FIRST SCREENSHOT - NO WAYYYYYYYY!!!!! I'm tickled beyond belief!!

Your second screenshot is what I ran into last night!!!! Almost identical! YIKES!

Indeed true! A LOGICAL GOTCHA! Thank you!

It's important to know basic chess rules. Advanced concepts are less important.

"The king can't move into check" is as basic as you can get, and that's all we need to know for these positions.

Reminds me of that one puzzle where the queen was pinned to the king but delivered checkmate because the pinner was pinned

I didn't see that mentioned when I read More > Rules. Your phrase should be mentioned under 'special situations' there. So a King can't move into check even if the attacker is all talk and no action. You summed it up, thank you! Those six words will be implanted in my brain!

I checked that article and it indeed doesn't seem to talk about that. It's pretty bad. The article tries to talk about too many things (like the rules of obscure chess variants and whatnot) while it leaves out important stuff.

There is an actual chess rule about this. Article 3.9 in the FIDE rulebook.

3.9 The king is said to be 'in check' if it is attacked by one or more of the opponent's pieces,even if such pieces are constrained from moving to that square because they would thenleave or place their own king in check. No piece can be moved that will either expose theking of the same colour to check or leave that king in check.

https://www.fide.com/FIDE/handbook/LawsOfChess.pdf

Thank you!! Yes indeed - I'm sure others will benefit from this pdf as well! A phrase that threw me the first month here was 'being flagged.' I kept picturing a football referee throwing a red flag onto the ground in response to infraction.  

For others newer to the game, it means for time to run out and it is good to read the rules here at More > Rules and read the pdf @magipi referenced immediately above.

I have been searching for this example. Do you happen to remember where I might find it? I love studying oddities (probably because I AM an oddity myself).