Number Ten is the usual recommendation for a first two-deck game, and the reason is one card. It deals the classic ten columns of four with only TWO cards face down instead of Rank and File's three, builds down in alternating colours, and lets packed sequences move as a unit. That extra card of information per column — ten more known cards at the deal — changes the game from a guess into a plan. Every rule in Number Ten is the friendlier option in its family, and the result is a two-deck patience you can actually reason your way through.
Twenty visible cards is enough to plan ahead, so plan. Before you touch the stock, scan the board for a card in one column that packs onto a card in another. Every such pair is a free exposure — it costs you nothing and turns a hidden card over. Work through all of them before dealing, then look again, because each reveal often creates another.
Keep packed columns packed. Because runs travel whole, a column already in alternating order is a single portable unit. Breaking it apart to gain one foundation card usually costs more than it earns. Break a run only to reach a face-down card underneath it.
Clear a column once its hidden cards are gone. Number Ten hides only two rows, so a column is often two moves from empty. That is a much better trade than in Emperor, where clearing a column throws away three unknowns. An empty column accepts a whole run, which is the move that unblocks everything else.
Deal last, always. There is no redeal, so the waste is a one-way street: a card you cannot place when it turns up is a card you will never see again. Spend every free tableau move before each stock click.
The Forty Thieves group is defined by a two-deck board of ten-ish columns feeding eight foundations, and its members differ only in a few dials: how much is hidden, whether you build by suit or by colour, whether runs may travel, and whether the stock comes round again. Forty Thieves proper sets every dial to hard — everything visible but suit-only building, single-card moves, no redeal. Emperor hides three rows. Rank and File adds run moves back. Number Ten turns the last dial the friendly way by hiding only two rows, which makes it the softest landing in the family and the natural place to start before working back up to the parent.
Number Ten 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.