How can I figure out this chess position?

Question

How can I deduct whose move it is by looking at a chess position?

Answer 1

Unless it's extremely early in the game, I don't know if you can.  Considering that moves can be "lost" in any number of ways (taking two moves to advance a pawn instead of the initial two-space move; moving a bishop out, then back, etc.), the board position alone probably won't be able to tell you.

However, you can look for context clues.  If one piece is forking two others (threatening capture on two pieces simultaneously) and neither of the targets is protected, then that player probably just moved.  The victim of the fork would certainly move to protect the more valuable piece, so you can probably assume s/he hasn't had the opportunity to respond yet.

Answer 2

In general it's impossible to tell whose move it is unless there are some clues in the position.  One obvious give-away is if one of the Kings is in check.  That side must be on move because it's illegal to leave one's King in check after making a move.

Actually, figuring out whose turn it is can be an interesting problem.  It's a variant on a type of chess problem called "retrograde analysis".  The goal of retrograde analysis is not to find the best move, but to figure out how a position came about.  The following link is one example.  You are given a chess board with a number of pieces on it.  You aren't told which pieces are black or white.  The goal is to prove which pieces must be black, which must be white, whose move it is, and how the position arose.  Try it.  It's quite a challenge.

Answer 3

Look at the chess clock,check the notation sheet,ask one of the players,your check the video of the game.