Emperor, also published as Deauville, takes the classic Forty Thieves board and hides most of it. Ten tableau columns of four cards are dealt — the first three face DOWN, the fourth face up — so thirty of the forty tableau cards are unknown when you start. Where Forty Thieves shows you everything and dares you to sequence it, Emperor shows you ten cards and asks you to find out the rest. That single change turns a planning puzzle into an exploration.
Play toward information, not toward tidiness. Every exposed card is worth more than the tempo it costs. When two moves are otherwise equal, take the one that turns something over. A board you can read is a board you can plan; a board you have merely arranged is still a guess.
Do not empty a column early. This is the counter-intuitive one. Clearing a column in Emperor means clearing three face-down cards you never got to see — you paid for a space with the information you needed. Dig a column down to its last hidden card and turn that card first.
Play the board out before every stock click. With no redeal, the waste is a one-way street. A card you skip is gone. Exhaust the tableau moves that cost you nothing, then deal.
Free the low cards of a suit, not just its ace. Two decks mean each rank appears twice, so a buried ace is survivable. A suit whose ace, two and three are all deep is not: both of its foundations stall, and you lose a quarter of your outlets.
The Forty Thieves group is one of the largest variant families in patience, and its members differ by remarkably little — the deal shape, the building rule, whether runs may travel, whether the stock comes round again. Emperor is the concealment branch. It keeps the family's ten-by-four board and one-card-at-a-time movement, softens the build to alternating colours, and then buries three quarters of the tableau. Rank and File deals the identical hidden board but lets packed runs move as a unit; Number Ten hides only two rows and moves runs as well, which is why it is the usual first two-deck recommendation. Play them in that order and you can feel exactly what each rule is worth.
Emperor runs in your browser — free, no download, no sign-up. Install it as an app on your phone or computer and it works offline. You get unlimited undo, a hint button that names a legal move, statistics that track your wins and times, and seeded deals: every game has a seed you can replay, so a board you enjoyed (or lost) can be played again exactly.