Gin Rummy
Two-player Gin Rummy with your melds found and grouped for you, your deadwood counted exactly, and three opponent strengths — free, private and running entirely in your browser.
How to play
You each get ten cards. On your turn you take one — from the face-down stock or the face-up discard pile — and then throw one away. You are trying to arrange your hand into melds: a set of three or four cards of the same rank, or a run of three or more in a row of the same suit.
Whatever is left outside your melds is deadwood, and it is what you are scored on. Aces are worth one, court cards ten, and everything else its face value. Once your deadwood is 10 or less you can end the hand by knocking as you throw; if it is nothing at all, that is gin.
Scoring
- A knock scores you the difference between the two deadwood counts — but first your opponent may lay their own deadwood onto your melds, which brings their count down.
- Gin scores you 25 plus their whole count, and allows them no lay-off at all. It is the most valuable thing in the game.
- An undercut — their count ending level with yours or lower — scores them 25 plus the difference. Knocking with a high count late in the hand is how it happens.
- In a match, first to 100 wins and takes a 100 game bonus plus 25 for every hand won, doubled if the loser never scored.
The melds are found for you
One card can often serve two melds — a seven that is both the third seven and the top of a club run — and choosing wrongly leaves points on the table. Zerdly searches every way of splitting your hand and shows the arrangement that leaves the least, grouped and labelled under the cards, with each leftover card carrying its own value.
The common shortcut — take the longest meld first and remove its cards — is right about 99.5% of the time. When it is wrong it is wrong by about thirteen points, which is a whole hand’s score. That is why this is done exactly.
Modes
- Single hand
- One hand, played out and scored. The quickest way in, and the default.
- 100-point match
- Hands until somebody reaches a hundred, then the game and box bonuses decide it.
- Teaching
- Your melds are highlighted as they form, the count is always on screen, and a hint is always there. Nothing is recorded.
- Daily deal
- Five hands, and everyone gets the same cards today. Reloading will not change them.
The opponent
It works out the same best arrangement of its own hand that you get shown, values a possible draw against the cards nobody has seen yet, and treats a card near one you took off the pile as dangerous to throw. It decides whether to knock by comparing its count against how far into the hand you are, rather than knocking the moment it can.
- Learner
- Plays the obvious card, knocks the moment it can, and does not think about what it is giving you.
- Steady
- Counts what has gone, avoids feeding you the cards you have shown an interest in, and waits a little for a better knock.
- Sharp
- Values every draw against the cards still unseen, holds out for gin when the hand is close, and throws what you have already shown you do not want.
The levels differ in how much they think and how consistently they play their best idea — measured, not asserted: over six seeds of paired hands, Sharp beats Steady by about two points a hand and Steady beats Learner by about four. They never differ in what they are allowed to see.
A few things worth knowing
- Throwing a high card early is usually right. A king is ten points of deadwood and can only ever belong to one run.
- Taking from the discard pile tells your opponent what you are collecting, and they will remember. Drawing blind tells them nothing — which is worth something by itself.
- Knocking with eight on the fourth turn is excellent. Knocking with eight on the twentieth is how you get undercut, because their count has been falling the whole time too.
- A pair whose other two cards are both in the discard pile is not a near-meld. It is two dead cards, and worth throwing.
Privacy and local play
Your hand, your settings and your record are stored on this device and nowhere else. There is no account, no sign-in and no gameplay request to any server. The reset button clears this game’s data and leaves every other Zerdly tool alone.
Questions
- Can the computer see my cards?
- No, and not as a matter of care. The only thing the opponent is ever given is one seat's view of the table, and that object has no field for the other hand — not an empty one, no field at all. What it does know is what you showed it: the cards you took from the discard pile in the open, and the ones you threw away. That is what any human opponent would know too.
- Does it work out my melds correctly?
- Yes, exactly, every time. Finding the best way to split a hand is harder than it looks, because one card can serve two melds — a seven that is both the third seven and the top of a run. The usual shortcut takes the longest meld first and orphans the rest. Zerdly searches every arrangement of the hand and takes the one that leaves the least, which is checked against an independently written brute force on thousands of random hands.
- Is the shortcut really that bad?
- It is right about 99.5% of the time — and when it is wrong it is wrong by about thirteen points, which is a whole hand's score. Measured over 20,000 random eleven-card hands, the greedy approach is beaten on 0.8% of them. That is the case for doing it exactly: not that the shortcut fails often, but that its failures are never small.
- Which house rules does this table use?
- The ace is low, so A-2-3 is a run and Q-K-A is not, and the ace is worth one. You knock at 10 deadwood or less, and gin is zero. Gin allows no lay-off. An undercut is the defender being level with you OR lower, not strictly lower. You may not throw back the card you just took from the pile. If the stock reaches 2 cards with nobody knocking, the hand is a wash. Going out on eleven cards — big gin — is not used here.
- Can I reload to get a better hand in the Daily?
- No, and not because it is forbidden. Each hand of the Daily is dealt from the date and that hand's number, so hand three is the same fifty-two cards however you arrive at it. Even a hand that washes because the stock ran out is part of the sequence, so everybody who reaches the replacement gets the same one.
- Is anything sent to a server?
- No. The rules, the shuffle, the opponent, the sounds and your saved hand all run in your browser. There is no account, and clearing this game's data leaves every other Zerdly tool untouched.