Diplomat Solitaire: two packs, one pass, and what 2,000 test games showed

By Admin · Research by the free-solitaire.nz team · Figures from our September 2026 simulation study

Diplomat is a relaxed-looking two-pack patience with a sting in its tail. Eight tidy columns of face-up cards sit in front of you, eight foundations wait above, and a big stock of 72 cards is turned over one at a time — once only. There is no second pass, so every card that goes to the waste pile and gets buried is a card you may never see again.

We wanted to know how that one-pass rule plays out in practice, so we built a bot that plays Diplomat the way a careful player would — seeing only the face-up cards — and let it play 2,000 deals under the exact rules on this site. It won 47.9% of them. A skilled human with Undo should do at least as well.

Diplomat at a glance

That makes Diplomat roughly a coin toss for a decent player — and even a lost game usually ends with most of the cards home. The bot averaged 76 of 104 cards on the foundations, win or lose.

How to play Diplomat

The layout

• Two standard packs shuffled together — 104 cards.
• Eight tableau columns of four cards each, all face up.
• Eight foundations, one for each Ace.
• The remaining 72 cards form the stock, turned one at a time onto a waste pile. There is no redeal.

The goal

Build all eight foundations up by suit from Ace to King.

How cards move

• Tableau cards build down by one rank, regardless of suit or colour. Any 6 may go on any 7.
• Cards move one at a time — you cannot lift a run in one go.
• Any card may go into an empty column.
• The top card of the waste pile can be played to the tableau or a foundation.

What makes Diplomat tick

Three rules shape almost every decision:

1. One pass through the stock. A card turned to the waste is only available while it is on top. Bury it under five more and you will need to play those five first.
2. Building ignores suit. This makes it easy to build, but a column like 9–8–7 of mixed suits can only be unpicked one card at a time, and only onto other cards or into empty space.
3. Single-card moves. Long mixed runs are heavy to shift. Empty columns are the only real room to manoeuvre.

In our 2,000 test deals, only 49.2% gave an Ace that was playable straight away. In the other half, the first job is to dig or to turn the stock until one appears.

Strategy that follows from the numbers

1. Treat the waste pile as a one-way street

Before you turn the next stock card, ask whether the current waste card can go anywhere useful. Once it is covered, it is effectively in a column you cannot see into. Our bot played better when it was penalised for letting the waste pile grow, and so will you.

2. Empty a column early — then be stingy with it

Four-card columns are short, so clearing one is realistic within the first few minutes. An empty column accepts any card, which makes it the most flexible space on the board. Use it to unpick a run or to rescue a waste card, not as a dumping ground.

3. Keep runs short and useful

Because runs move one card at a time, a long run built on the wrong card can be almost impossible to shift. Prefer building on cards you will not need soon, and avoid covering a low card that the foundations are waiting for.

4. Remember there are two of everything

With two packs there are two 7s of hearts, two Aces of spades and so on. If one copy is buried, the other may be sitting in the stock. That can make a stalled game come right late on — worth remembering before you give up.

5. Use Undo to test the stock

On this site Undo is unlimited, so you can turn a few stock cards to see what is coming, then step back and plan. Our bot had no such luxury and still won nearly half of its games.

Common mistakes we see

• Turning the stock on autopilot. With 72 cards and no redeal, flicking through the stock quickly is the fastest way to lose. Each turn is a decision.
• Filling an empty column with the first card to hand. Any card can go there, so choose the one that unlocks the most — often a card that is sitting on a low card the foundations need.
• Building tall mixed runs. They look tidy but can only be dismantled one card at a time. Four or five cards is usually plenty.
• Forgetting the twin cards. If you are waiting on a 3 of clubs, remember there are two of them. Placing a card on top of one copy is less costly when the other is still to come.

The common thread is patience. Diplomat rewards the player who slows down at the moments that cannot be undone in a real game: burying a waste card and committing an empty column. On this site you do have Undo, so treat it as a learning tool — replay a decision two ways and see which line keeps more cards alive.

Playing Diplomat on free-solitaire.nz

Diplomat here is free, runs in any modern browser, and needs no download, no sign-up and no email address.

• Large, clear cards and readable text, plus a zoom control — useful with 104 cards on the table.
• Hint, unlimited Undo, Restart and Auto Play to finish a solved game.
• Drag and drop, or tap a card and then where it should go.
• Wins, time and moves tracked for the current game.
• Sound can be switched off, with fullscreen mode and a choice of table colours.

There is no gambling, nothing to buy and no timer. It is the sort of game that suits a slow Sunday in Dunedin as well as a quick break at work.

How we did the research, step by step

The free-solitaire.nz team ran this study in September 2026. These are the steps we took, in order.

1. Read the rules from our own game. From this site's game code: 104 cards, eight foundations, eight columns of four face-up cards, a 72-card stock turned one card at a time with no redeal, building down regardless of suit, one card per move, and any card into an empty column.
2. Rebuilt the game in code. We wrote a program that deals and plays Diplomat by exactly those rules.
3. Generated numbered deals. 2,000 deals, each from a fixed seed, so anyone can replay them.
4. Built a player that only sees what you see. Our bot does not know the order of the stock. Before each move it searches up to 300 positions ahead over tableau and waste moves.
5. Gave it a simple sense of a good position. It favours cards home, empty columns and tidy runs, dislikes cards sitting on lower cards, and turns the next stock card only when nothing else improves the position. It never uses Undo.
6. Played and counted. It won 957 of 2,000 deals: 47.9% (95% range 45.7–50.0%). Across all games it got 76 of the 104 cards home on average, and a win took about 351 moves including stock turns.
7. Inspected the opening deals. In 49.2% of deals an Ace can be played straight from the opening columns.
8. Looked for outside figures. We did not find a published winnability figure for Diplomat, and we did not build a solver for it, so there is nothing to compare against. These figures are original.

What this means: the bot thinks only a short way ahead and cannot undo, so 47.9% is a floor for a skilled player, not a ceiling. Ranges are 95% confidence intervals.

The technical side

Diplomat is simulated in diplomat.py, written in Python 3.11 with the standard library only. A shared runner.py spreads the deals over 19 worker processes with Python's multiprocessing, and each deal is shuffled from its own numbered seed, two full packs at a time.

• The bot runs a best-first look-ahead of up to 300 positions over tableau and waste moves, keeping a set of positions already explored. It never sees the order of the stock. It scores positions by cards home, cards stuck on top of lower cards, links and empty columns, and turns the next stock card only when nothing improves the score.
• Scale. The 2,000 deals took about 14 minutes; with 104 cards and long games, Diplomat was one of the slower runs.
• The 95% range is a Wilson score interval.

There is no published figure for Diplomat to test against, so we treat the bot's result strictly as a floor and give its full range rather than a single number. We used an AI assistant (Claude, by Anthropic) to help write and review the code and draft this page. The AI did not produce the figures; they come from running the code, and the team checked the results before publishing.

Frequently asked questions

Is Diplomat hard?

It is middling. Our bot won just under half its games, and even lost games usually finish with most cards home. It is easier than four-suit Spider and harder than one-suit Spider.

Can I go through the stock twice?

No. Diplomat on this site deals the stock once, with no redeal. That is the rule that makes careful waste management so important.

Why can't I move a whole run?

Diplomat moves one card at a time. It is part of the game's character — empty columns are your workspace for unpicking runs.

How long does a game take?

Our bot needed about 351 moves (including stock turns) to win a game. For most people that is a comfortable 10 to 20 minutes.

Do I need to sign up?

No. There is nothing to install and no account.

What should I try next?

If you like two-pack games, try Spider with two suits. For a single-pack puzzle with everything face up, try Baker's Solitaire. The full list is on our games page, and more research lives on the blog.