I got the idea for this Puzzle during a fight between my Green Gang and the Dark Knight's team - along with Gotham's men and women in blue. It took place in a Gotham district where blocks are arranged in a very regular pattern ; my gang was trying to capture Mayor Hill, and the Police and Batman were trying to capture me.

I was on some building supervising the operation, and it struck me how similar this all was to a Chess game... when I suddenly got knocked to the ground by Robin. I thought "well, Pawn checks King" ; and later, taken to Arkham again, I made this little problem up. I dedicate it to Batman's Brave Dark Soldier.

 

This problem isn't your ordinary Chess problem : it's not about what to move next, it's about what happened during the game. The only things you have to care about are the rules of Chess, not how to win - in that sense, it's more of a Logic problem than a Chess problem. Don't assume at all the moves were reasonable : something a sensible Chess player would never do, like promoting a Pawn into a Knight after getting it to the opponent's side, can have happened here.

Here's the Riddle : knowing Blacks two last moves were Checks, and that only Chess rules matter, what was Whites last move ?

You can submit your answer (which Piece moved, from where to where, if it took a Piece and which one) by using the TV screen and TV buttons on my right ; or - and I do advise you to do so - follow a series of step-by-step Puzzles through my interactive, animated Help Quiz.