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Download on Google Play- 1 player with a standard 52-card deck.
- Deal 4 reserve piles of 4 cards (top card face-up).
- Place next stock card as first foundation; stock deals in 3s.
- Play cards to foundations by suit if the rank appears in the row above.
- First foundation accepts any card of its suit freely.
- Play top reserve cards or top waste card. Unlimited redeals.
- Win by placing all 52 cards on the four foundations.
- Partial score by counting placed cards.
Rules
Osmosis, also known as Treasure Trove, is a unique solitaire card game where cards are played to foundations by suit, but with a distinctive constraint: a card can only be placed on a foundation if a card of the same rank has already been played to the foundation row above it. This osmotic filtering mechanism gives the game its name and creates an unusual strategic puzzle.
Objective
Move all 52 cards to four foundation piles, each built by suit, with the constraint that each rank must appear in the foundation above before it can be played.
Setup
- Players: 1 player (solitaire).
- Deck: Standard 52-card deck.
- Reserve: Deal 4 piles of 4 cards each in a column on the left, with only the top card of each pile face-up.
- First foundation: Place the top card of the stock next to the top reserve pile to start the first foundation. This card determines the starting rank.
- Stock: The remaining 35 cards form the stock, dealt through in groups of 3.
Gameplay
- Foundation building: The first foundation (top row) can accept any card of its suit in any order. The second foundation can only accept cards of its suit if the same rank already appears in the first foundation row.
- Osmosis rule: The third foundation follows the second, and the fourth follows the third. Each row filters through the row above it.
- Starting new foundations: When a card of the starting rank appears (from the reserve or stock), it begins a new foundation in the next row.
- Reserve play: Only the top card of each reserve pile is available. When it is played, the card beneath is turned face-up.
- Stock dealing: Deal 3 cards at a time from the stock to a waste pile. The top waste card is always available for play. Redeal the waste pile as needed (unlimited redeals).
Scoring
- Win condition: All 52 cards are moved to the four foundations.
- Partial scoring: Count the total cards placed on foundations when the game stalls.
- Win rate: Osmosis has a moderate win rate, estimated around 1 in 6 games with optimal play.
Variations
- Peek: Allow looking at all cards in the reserve piles (not just the top card) for an easier game.
- Single-card deal: Deal one card at a time from the stock instead of three for a higher win rate.
Tips and Strategies
- Focus on building the first foundation quickly, as all other foundations depend on it.
- Track which ranks have been played to the first foundation so you know what is available for lower rows.
- Do not rush to start new foundations; sometimes it is better to build up the first row before expanding.
Tips & Strategy
Build the first foundation aggressively since it unlocks all cards below. Track ranks carefully across foundation rows. Be patient with the stock — unlimited redeals give you time to find the right cards.
The cascade dependency between foundations means that the first foundation essentially controls the pace of the entire game. Building diverse ranks there early gives the most flexibility.
Trivia & Fun Facts
The game is named after the biological process of osmosis because cards filter through from the top foundation row to lower rows, much like molecules passing through a membrane.
Why is this solitaire game called Osmosis?
History & Culture
Osmosis first appeared in patience game collections in the early 20th century and quickly gained popularity for its unique filtering mechanic that set it apart from conventional solitaire games.
Osmosis holds a special place in solitaire culture for its distinctive mechanic. It has been featured in most major digital solitaire collections and is a favourite among players who enjoy unconventional patience games.
Variations & House Rules
The Peek variant allows viewing all reserve cards for easier planning. Single-card dealing from the stock significantly increases the win rate.
Deal cards one at a time from the stock for a more winnable game. Allow peeking at reserve piles for a planning advantage. Limit redeals to 3 for added difficulty.
