Rules
Osmosis Solitaire rules at a glance
- Use one standard 52-card deck.
- Deal four reserve piles of four cards each; only each pile's top card is playable.
- The seventeenth card starts the top foundation and sets the seed rank.
- The top foundation accepts any card of the seed card's suit, in any rank order.
- The other three foundations must start with the seed rank in unused suits.
- A lower foundation can accept a card only after the same rank appears in the foundation directly above it.
- Deal up to three cards from the stock to the waste; only the top waste card is playable.
- Reserve and waste cards move only to foundations. There is no tableau building.
- When the stock is empty, redeal the waste only if that pass made foundation progress.
- Win by moving all cards to the four foundations.
How to play
How to play Osmosis Solitaire
Osmosis Solitaire is a foundation game, but it does not ask you to build A, 2, 3, and so on. The first foundation acts like a filter. Once a rank enters the top row, that rank can move into the second row in its matching suit. Once it reaches the second row, the same rank becomes available to the third row, and then to the fourth.
The deal begins with four reserve piles on the left side of the table. Each reserve pile holds four cards, but only the top card is available. The next card dealt after those sixteen cards starts the first foundation. That card decides two important details: the suit of the top row and the seed rank that the other three foundations must use as their first card.
On your turn, select an exposed reserve card or the top waste card. If it fits a foundation, play it there. If no exposed card fits, deal three cards from the stock to the waste and check the new top waste card. The game is won when every card has moved to a foundation.
Foundations
How the Osmosis foundation rule works
Suppose the seed card is the 7 of hearts. The heart row can take any other heart whenever that card is exposed. The second foundation cannot begin with a 9 or a queen; it must begin with a 7 in another suit. After the 10 of hearts reaches the top row, the 10 of the second row's suit becomes legal there. The rank has filtered down one step.
The same check repeats between every pair of foundation rows. A card for the third foundation needs its rank already present in the second foundation, not merely in the top foundation. This is the rule that gives Osmosis its name and its quiet difficulty.
Layout
The layout on this page
This version uses four reserve piles, four foundation rows, one stock, and one waste pile. Reserve piles reveal naturally: when a top reserve card moves away, the next card in that pile becomes available. Hidden reserve cards cannot be inspected or moved early.
The stock deals three cards at a time. The waste behaves like a strict stack, so only the top card can move. When the stock is empty, the waste can be turned back into the stock only if the current pass has played at least one card to a foundation. That keeps redeals useful without allowing endless no-progress cycling.
Examples
Legal and illegal move examples
If the top foundation is hearts and already contains 7, 10, and king, then any exposed heart can still move there. Rank order does not matter in the top row. If the second foundation is spades, the 10 of spades is legal because the 10 of hearts is already above it. The 4 of spades is not legal until a 4 appears in the heart foundation.
If the third foundation is diamonds, the 10 of diamonds needs the 10 of spades in the second row. It is not enough that the 10 of hearts exists in the top row. An empty lower foundation is stricter: it can start only with the seed rank, and only in a suit that is not already assigned to another foundation.
Strategy
Osmosis Solitaire strategy
Start by watching the seed rank. The lower foundations cannot do anything until their seed cards appear, so those cards are high-value unlocks. If a seed-rank card is sitting on top of a reserve pile or waste pile, playing it usually matters more than playing another harmless card to the top foundation.
Feed the top foundation with ranks that help the rest of the table. A random top-row card is not always urgent, but a top-row card whose matching suit card is visible below may unlock an immediate chain. Before you draw from the stock, scan the reserve tops and the waste top: one foundation move can expose a hidden reserve card and also justify another stock pass later.
Be careful with the stock. Dealing three cards can bury a playable waste card under two new cards. If a reserve move is available, it is often worth taking before drawing again because it may open a rank that makes the current waste card useful. The game rewards patience more than speed.
Mistakes
Common Osmosis Solitaire mistakes
- Assuming foundations build in normal rank order.
- Ignoring the seed rank cards that start the lower foundations.
- Dealing the stock while a reserve move is already available.
- Expecting a lower foundation to use any rank that exists in the top row.
- Forgetting that only the waste top card is playable.
- Treating hidden reserve cards as if they can be planned exactly; they cannot in this version.
Winnability
Is Osmosis Solitaire winnable?
Osmosis Solitaire is not always winnable. The initial reserve order can hide important seed-rank cards under blockers, and the stock can present useful cards at awkward times. A deal can fail even when you understand the rules.
Skill still matters. Good play recognizes which ranks are about to unlock lower rows, avoids unnecessary stock deals, and uses each bit of foundation progress to earn another pass through the waste. We do not claim a win rate here because a meaningful number should come from this exact implementation after many measured deals.
Variants
Osmosis, Treasure Trove, Peek, and house rules
Osmosis is also known as Treasure Trove. The core idea is the same: one suit row opens ranks for the next suit row, which opens ranks for the next. Different rule books and digital versions vary in small stock details, especially how redeals are handled.
Peek is the most important nearby variant. It plays like Osmosis, but the reserve cards are visible, so the puzzle becomes more planned and less dependent on memory or surprise. This page uses traditional hidden reserve piles. If Peek is added later, it should be a separate mode or page because seeing all reserve cards changes the decisions dramatically.
Comparison
How Osmosis compares with other solitaire games
Osmosis sits near Calculation and Canfield, but it has its own rhythm. Like Calculation, it cares about rank availability rather than ordinary suit sequences. Like Canfield, it gives you a small reserve and a stock that can make or break the deal. Unlike Klondike, there are no descending tableau builds, no color alternation, and no king-only spaces.
If you enjoy games where a single visible card changes what the whole table can do, Osmosis is worth learning. It is calmer than Golf or TriPeaks, less open than FreeCell, and more rule-driven than Aces Up. The pleasure is in seeing one rank unlock a neat chain down the foundations.