Ali Baba is what Forty Thieves becomes when you take away one deck, hand the player the four Aces, and let sequences move as a unit. Ten columns of four cards sit face up, the Aces are already on their foundations, and the stock holds only eight cards. Almost everything is visible and almost everything is legal, which makes this one of the friendliest doors into a family with a reputation for being merciless. Free in your browser, no sign-up.
Goal: build all four foundations from Ace to King by suit.
With only eight cards in the stock, this game is almost entirely a tableau game. Nearly every decision you make is about the forty cards already in front of you.
The name is the joke, and the joke is accurate. Forty Thieves is the two-deck standard of this family; Ali Baba is its one-deck cousin, and the forty cards on the board are the forty thieves. The PySol Fan Club collection builds it directly on Big Forty — a one-deck game of ten columns of four — by dealing the Aces to the foundations first, which shortens the stock from twelve cards to eight and turns the game from a dig into a puzzle you can see all of.
Two of its rules deserve their citation, because they are what make it play so much lighter than its parent. Sequences move as a unit: the PySol row stack it inherits carries an unlimited move allowance, and Goodsol says the same in words, calling the game "much lighter and easier than Forty Thieves ... because sequences can be moved". And an empty column accepts anything, because the underlying stack keeps its default of any rank — BVS Solitaire states it plainly as "you can fill the space with any card or legal sequence of cards".
One rule here is a deliberate choice between conflicting sources, and it is worth naming. PySolFC allows unlimited passes through the stock; BVS Solitaire says there is no redeal. This version follows BVS. Politaire, which solved both variants across a large sample of deals, reports that unlimited passes "only slightly increase the win rate", so the cost to the player is small — and a single counted pass is what lets the game tell you honestly when a position is genuinely finished.
For the same family at full two-deck strength, play Forty Thieves or Josephine, which shares this exact ten-by-four board with two decks. For the other one-deck member, play Fortune's Favor. For a two-deck board where runs also travel, try Number Ten.
One honest note on difficulty. A random-play sample at one site reports roughly 28% wins, which is unskilled play rather than a solver's verdict, and Politaire's solver study does not publish its figure in the text we can reach. Neither number is quoted here as fact. What can be said is that PySolFC rates the game balanced rather than lucky, and that with everything face up, a good player should do considerably better than a random one.