# Playing with Undo – Post Mortem

As the Tokyo Olympics draws to a close, so does our foray into the world of playing Spider Solitaire with undo privileges.

To be honest, I am not really a fan of playing with undo (with one important exception, which I assume the assiduous reader of this blog knows by now). It reduces the game to an exercise in long-term calculation and almost every hand is winnable. In some sense it plays a lot like Freecell, and it is well known Freecell is almost always winnable. Schistocerca Americana agrees that Four-Suit sans Z-key is indeed the Cadillac of Solitaire Games.

The hand was originally intended as an exercise in obtaining cheevos, but it soon became clear we would struggle from the beginning just to win the hand. After conceding a humiliating defeat, I changed this hand into an exercise in playing with undo. I was hoping this hand would provide a challenge – precisely because I lost badly without undo privileges.

With undo, the hand was probably not too hard, given we got an empty column before having to deal any cards from the stock. There were no special tricks required other than careful book-keeping with Excel Cheatsheet and keeping an eye for opportunities to remove complete suits.

Going back to the game state below: suppose we somehow managed to reach this position without undo (and hence no knowledge of unseen cards). If we tried to turn over all cards in column 8 we would get quite the scare – it’s still a win, but it would be pushing way beyond our comfort zone given we have four suits removed and three empty columns. For this reason alone, I would estimate this hand to be extremely hard sans undo. It’s obviously winnable but one would probably need to play a number of sub-optimal moves and get lucky.

I should also thank SA for his wonderfully silly digressions and forays into binge-playing Microsoft Spider Solitaire in the name of Scientific Research. However, I am not sure why he believes 10/15 equals 40 per cent – but to be fair I’ve seen worse brain farts on Cracking the Cryptic. In any case SA definitely has what it takes to become one of the top players sans Undo. If there ever were a massive Zynga Spider Solitaire tournament and Zynga were a reputable game company then SA has got it made 😊

As of next week, the U-bomb is back to being a rude word again and will be censored via rot13.