"Yes The Rook Is Pinned But..."

Regarding the Daily Puzzle of May 9th:

The reason the White Knight cannot be captured is because the g Rook pins the pawn:  if the pawn captured, it would expose the King to check and therefore, it is an illegal move.

It's irrelevant that the g Rook is itself pinned by the Bishop:   the difference is between a pinned piece not being able to move [Black's g pawn] and the pinned piece exerting influence [White's g Rook].

Here's a variation if White played something silly like 2. b4:  2. ... Qxg4  3. Reg1 [preventing 3. ... Qxg2#] Nxf2#:

Here the g2 Rook cannot capture the Knight because it [the Rook] is pinned by the Bishop.

The key question to ask yourself:  "Does my proposed move put my King into check?"

- If "yes", you cannot make that move

- If "no", you can make that move

Make sure you understand the difference between these two scenarios:  it will allow you to win [or save] more games.

Here is a very cool example:  White to move and mate in 1 [saw this on Reddit].

1. Qb3#

Yes, the Queen is pinned.  However, Qb3 does not expose the White King to check, so it's legal.  Furthermore, the Bishop cannot capture the Queen because it is also pinned.

The reason the Queen can move is because it moved along the direction of the pin.  It can't move vertically or horizontally but it can move diagonally along b2-g8 since that is the pin line.