Here is a new retrograde chess puzzle based round a new idea. **In the position below, White’s 9th move was an en passant capture. Can either player still castle? (10+9) FEN: r2qk1n1/ppppp2P/P4P2/8/8/3PP3/4PPP1/4K2R Please provide your reasoning in your answer. Have fun! :-)

I tried to find a puzzle tagged both cryptic-clues and computer-science but found none. OK, here's one: 8-bit mathematical group, then 32-bit hard canine explorer (7,3,5) (is it tagged correctly?)

Alice decides to write her mathematics-loving girlfriend a cute maths equation in her valentine's day card: i! -------- u!(i-u)! She gives the card to her girlfriend. After reading the equation, her girlfriend begins to cry and runs off. Explain what happened. (My first time posting something...

Explain how the figure below was created. - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - ...

Line 1: Beatles drummer Ringo (5) anchors that absorb water/nutrients (5) Air Force base in Nebraska (6) U.S. state with 8 bordering states (9) Spanish tennis star David (6) elliptical life containers (4) river in Alan Jackson's hit (13) Line 2: Paul's letter to Thessalonica, abbrev. (5) Bella (n...

Prove that the equality, 1/a+ 1/b + 1/c + 1/d + 1/e + 1/f = 1 has no solutions in odd natural numbers. P.S. I think what it means is that if a, b, c, d, e and f are all odd natural numbers then the above equation cannot be true. From the excellent book, Mathematical circles Russian experience

'before this Lady changed her name when Valiums were her claim to fame this was a place nearest the street where old friends Joe and Jacob meet' i have tried so many things but none have been correct! any help is appreciated. previous puzzles in the arg have been ciphers so it could be hidden or ...