Osmosis Solitaire

A seed rank sets the pace

How to play Osmosis Solitaire

Sixteen cards go out as four reserve piles of four, face down except for the top of each. The seventeenth card is dealt to the top foundation row, and it settles two things at once: that row's suit, and the rank every other row will have to begin with.

The top row is the loose one. It accepts any card of its suit whenever you have one, in whatever order they turn up. The three rows beneath it are gated: a card enters only if that same rank is already sitting in the row directly above. Ranks filter downward, which is where the name comes from.

Rows also open in order. Row two starts when a seed-rank card appears in a suit not yet in use; row three cannot start until row two has; row four waits for row three. Cards reach the rows from the top of a reserve pile or from the waste — never from one reserve to another, because Osmosis has no tableau at all.

Row by row

Which cards each row lets in

Feeding the reserves

Osmosis Solitaire strategy

Feed row one with intent. It is the only row that takes cards freely, and everything below depends on what is in it. When you have a choice of cards for row one, play the rank that unblocks a card you can already see waiting.

Empty the reserves before you touch the stock. Every reserve card removed exposes another; every stock deal buries three. Reserve depth is the resource that decides most deals, and working it costs you nothing.

Open the lower rows early, even for one card. A started row is a row that can start collecting. The cost of leaving row four unopened until late is that the ranks piling up above it have nowhere to filter into.

Track the redeal. The waste only returns as stock if the pass produced a foundation play, so late in the game a single banked move is the difference between another pass and the end of the deal.

Three ways rows stay shut

Where Osmosis deals go wrong

Filling row one out of order because you can

Row one takes anything of its suit, which makes it feel free. It is not. Every card you put there opens that rank for row two, so the order you feed it decides what the rows below can do. Playing the ranks you can see waiting in the reserves is worth far more than playing whichever heart happens to be on top.

Dealing the stock before working the reserves

A stock pass buries three cards and only exposes one. Exposed reserve cards, by contrast, reveal a new card the moment they leave. Squeeze every legal reserve move out before touching the stock, because reserve depth is the resource that runs out first.

Losing the redeal without noticing

The waste only comes back if the pass made foundation progress. If you deal the last of the stock while nothing is playable, the game is over then and there — not when the waste runs out. Count the stock down and make sure a playable card is banked before you burn the final deal.

Names

Osmosis and Treasure Trove

Treasure Trove is the older name for the same game, and you will still find it under that heading in printed patience collections. Osmosis is the name that stuck, because it describes the mechanic: ranks seeping down from one row into the next.

There is also a well-known open variant called Peek, in which the reserve piles are dealt face up so you can see all sixteen cards from the start. That removes almost all the guesswork about which seed-rank cards are buried and where. This page deals the reserves face down, in the traditional way.

Osmosis odds

Is Osmosis Solitaire winnable?

Some deals are not, and you can often tell fairly early. If two seed-rank cards sit deep in reserve piles and the stock pass stops producing foundation plays, the rows below simply never open and no amount of correct play will change it.

Skill still matters a great deal, more than in most reserve games. The order you build row one in, the discipline to exhaust reserves before dealing, and the timing of the last stock pass are all real decisions with real consequences. We do not publish a win rate: it swings sharply with the stock rule, and this page deals three at a time with a progress-gated redeal.

Reserve relatives

Osmosis against the other reserve games

What separates these games is the rule that decides when a card is allowed onto a foundation. Osmosis is the only one here where that rule points at another pile rather than at a number.

Canfield is the closest relative — one dealt card fixes a rank there too — but it builds in strict sequence, so its reserve is a queue rather than a set of keys.