Fair Play: How the Cards Are Shuffled and Dealt

You should be able to check that a card game is honest, not take it on trust. This page explains how the cards are shuffled, what the computer players know, and what this site keeps about you, which is very little and all of it in your own browser.

A performer's hands in costume sleeves shuffling a deck of cards over a cloth.

How the cards are shuffled

Every match starts from a deal number, shown on the table as, for example, Deal #4,203,117. It is a whole number between 1 and 4,294,967,295. A new deal number comes from your browser's cryptographic random-number source, the same kind used for security, not from the everyday random function that programs often use.

Each hand of the match is shuffled from two things only: the deal number and the number of the hand. The shuffle itself is the standard Fisher–Yates method, which gives every possible order of the deck the same chance. Because nothing else goes into it, the same deal number with the same rule options always produces the same cards, hand after hand, on any computer, phone, or tablet.

Replaying a deal

Open the Menu and choose Replay this deal to start the whole match again from the first hand, with the same rules and the same levels. The computer players' choices also come from the deal number, together with their seat and how many moves have been made. So if you replay a deal and make exactly the same plays, they will make exactly the same plays. Change one card and the rest of the hand can go differently, which is the point: you can find out whether another lead would have saved you.

A deal can also be shared. The deal details (see below) include a link that opens the same game at the same deal number, so a friend can play the very cards you played.

Today's deal

Each game has a Today's deal in the Menu. Its deal number is worked out from the name of the game and the date, so everyone who plays that game on the same date, with the same options, gets the same cards. The date is the one on your own device, so the deal changes at your local midnight. Your result goes into the game's statistics, which list your Today's deal results for the last seven days you played.

What the computer players can see

A computer player is handed exactly what a person in its seat could know at a real table: its own cards, the cards that have been played, the bids, the score, and anything else that is face up. In Gin Rummy that includes the cards you picked up from the discard pile, because your opponent saw you take them. It never sees your hand, the other players' hands, or the order of the cards left in the deck.

It also doesn't know which seat is yours. It cannot read your statistics, and it does not adapt to whether you are winning or losing. The level you choose before the deal stays the same for the whole match, whatever the score.

At the end of every hand you can press Show all hands to see every player's cards, so you can check for yourself what each computer player was holding when it made its plays.

The three levels

You choose the level of your opponents before the deal, and in Spades and Euchre you choose a separate level for your partner. Standard is the starting choice.

Easy: Plays legal, plausible cards with little planning, and now and then makes a loose play. In Hearts, for example, it passes its highest cards and otherwise plays almost at random, apart from dumping points when it can't follow suit.
Standard: Plays by the sound habits of a careful player. In Spades it never overtakes a partner's sure winner and covers a partner who bid nil; in Hearts it ducks, flushes out the Queen of Spades, and shoots the moon only with a strong hand.
Expert: Adds look-ahead. In Hearts, for example, when it follows to a trick, it deals out the cards it cannot see many times over, in every way that fits what it has seen so far, plays each sensible card through to the end of the hand, and keeps the one that does best on average. It is guessing from the evidence, the way a strong player does; it is not peeking.

Hint shows the play an Expert player would make in your seat. Undo takes you back to your previous decision in the current hand.

What your browser keeps

There is no account and no sign-up, and nothing about your games is sent anywhere. Everything is kept in your browser's local storage on this device:

your table settings: the deck, suit colors, card size, speed, and the other choices in Table settings, plus the rule options and levels you last chose for each game;
one saved game per game, updated after every move, so the table can offer to resume it;
your statistics for each game: matches played and won, results by level, your best final score, your winning streaks, and your Today's deal results.

If you clear this site's data in your browser, all of that is erased. If your browser blocks storage, as some private windows do, the games still work, but nothing is kept once you close the tab.

Backing up and moving your statistics

Open the Menu, choose Statistics, and find Back up your statistics. Copy the text there and keep it somewhere safe, such as an email to yourself or a note. It holds your settings, saved games, and statistics for every game on the site. To restore it, on this device or another one, open Statistics in any game, paste the text into Restore from a backup, and press Restore. What you restore replaces the same items in that browser.

Reporting a problem with a deal

If a hand looks wrong, open the Menu and choose Copy deal details. You get a short block of text with the game, the deal number, a link that replays it, the rule options, the levels, and the moves played so far, in order. Paste it into an email to hello@solocardgames.com and say what you expected to happen. With that text the exact deal can be replayed and checked, move by move.

Fair play