Twenty-Nine Help

Twenty-Nine Rules

Twenty-Nine is played with 4 players using a 32-card deck. The basic rules are described here. You may customize the rules to your liking in Rule Options.

The deck contains the 7, 8, 9, 10, J, Q, K, and A of each suit. You form a team with the player sitting across from you. The object is to capture enough card points to make your team's bid while preventing the opponents from making theirs.

The game consists of multiple hands. Each team accumulates points as the hands are played. The game ends when a team reaches either +6 or −6 points, and the team with the higher score wins.

Each hand consists of six stages: the initial deal, bidding, choosing trump, the second deal, playing, and scoring.

Initial Deal

At the start of the game, the dealer is chosen randomly. The deal then rotates counterclockwise after each hand. Four cards are dealt to each player.

Bidding

Bidding begins with the player to the dealer's right and proceeds counterclockwise. A player may bid or pass. Once a player passes, they may not bid again.

The first player must bid at least 16 or pass. A later bidder must make a higher bid or pass. The current high bidder may match a subsequent bid or pass, creating a contest between those two players until one passes. Bidding then continues with the next player who has not passed. If the first three players pass, the dealer must bid 16.

Choosing Trump

The player who wins the bidding is the declarer. The declarer chooses the trump suit for the hand. Trump remains hidden from the other players until a player cannot follow the suit led and must discard. Trump is then revealed automatically. See Rule Options for other ways to choose and reveal trump.

Second Deal

After bidding ends and trump is chosen, 4 more cards are dealt to each player. Each player now has 8 cards.

Play

The hand consists of 8 tricks. Each trick contains 4 cards, 1 card from each player. The player who plays the first card is the leader, and the suit of that card is the suit led. The highest card of the suit led wins unless trump is effective and a trump card is played; in that case, the highest trump wins.

Cards rank from low to high as follows.

7, 8, Q, K, 10, A, 9, and J.

Play has two phases. During the first phase, the hidden trump suit is not effective, so the highest card of the suit led wins each trick. By default, the second phase begins when a player cannot follow the suit led. Trump is revealed automatically before that player discards and is effective beginning with that player's play. A trump card then beats every nontrump card.

An advanced option instead gives a player who cannot follow suit the choice to reveal trump. A player who reveals trump must play a trump card when able. A player who chooses not to reveal may discard any card, and play continues without an effective trump suit until a player chooses to reveal it.

Once revealed, the trump choice is shown using the 3 of the selected suit. For a notrump contract, a joker is shown instead.

The player to the dealer's right leads the first trick. Play proceeds counterclockwise, with each player playing one card. Players must follow the suit led when able. A player who cannot follow suit may play any card, with one exception: after trump has been revealed, the player may not undertrump—play a trump lower than the highest trump already on the trick—unless no other card is available.

After each player has played a card on the trick, the winning player takes the trick and places it aside until the scoring stage. This player is the leader of the next trick. The play stage continues until players have no cards left in their hands.

Scoring

After all tricks have been played, the card points captured by each team are counted. There are 28 card points available.

• Jack. 3 points
• Nine. 2 points
• Ace. 1 point
• Ten. 1 point

The 7, 8, Q, and K are not worth any card points.

If the declarer's team captures at least the number of card points bid, they make the contract and add 1 point to their game score. If they capture fewer points than they bid, they lose 1 point. The defenders' game score does not change.

The game ends when a team reaches either +6 or −6 points. The team with the higher score wins.

Web Links

There are many helpful websites discussing Twenty-Nine. Here are a few we found especially useful.

• Wikipedia
• Pagat.com

Preset Game Rules

Twenty-Nine is played with many different rule options. NeuralPlay includes the following ready-to-play presets. See Rule Options to customize the rules.

• Basic (no 7th card). Uses the rules described in Twenty-Nine Rules. Trump is revealed automatically before the first discard.
• Standard (7th card). Enables 7th-card trump, notrump, double, redouble, single hand, marriage, and invalid-deal cancellation. Players are asked whether to reveal trump when they cannot follow suit.

Learning Features

NeuralPlay Twenty-Nine offers many features to help you learn and improve your play. These features may be enabled, disabled, or adjusted in Settings. The features include the following.

• Hints. By default, the AI shows a hint when you ask for one. In Settings, you may ask the AI to always show a hint, or ask the AI to check your bid or play and show a hint only when its choice differs from yours.
• AI points estimate. When enabled, each hint shows the estimated number of game points that will be scored for each legal play. This is an expected value averaged across many simulations. The AI-suggested play may differ from the play with the highest estimate because of strategy or simulation noise.
• Card counter. When enabled, a counter shows which cards have been played.
• Analyze bid. When enabled, an "Analyze" button appears during bidding. Tap it beside a proposed bid to estimate the chance of making that bid.
• Competitive mode. Enable competitive mode to play without assistance. Hints, undo, viewing all hands, and other learning aids are disabled.

Rule Options

NeuralPlay Twenty-Nine offers many popular rule options so you can customize the game to your liking. Basic and standard rules are included as presets. Options include the following.

Bidding

• Notrump. Allow the declarer to choose notrump. No suit is trump during play.
• 7th card. Allow the declarer to have their 7th card determine trump. This card is visible to the declarer when dealt, but will not be revealed to other players until the trump suit is revealed during play. The declarer cannot play the 7th card before trump is revealed unless it is their final card.
• Double and redouble. Disallow both, allow only a double, or allow both a double and redouble. After trump is chosen but before the second deal, the defenders are each given an opportunity to double the contract, making it worth 2 game points. When redoubling is allowed, each member of the declaring team may respond to a double by redoubling, making the contract worth 4 game points. If bids of 21 or more are worth double and such a bid has already been doubled, redoubling is not offered because the contract is already worth 4 game points.
• Single hand. After the second deal, allow each player an opportunity to choose a single hand. The player who chooses it becomes the declarer and plays notrump without a partner against both opponents. The declarer must capture all 8 tricks. Success earns 3 game points; failure loses 3 game points.
• Cancel invalid deals. Cancel and redeal when any of the following occurs.
  • A player has 8 cards and no point card.
  • A player has all 4 jacks.
  • The defenders have no trump cards.
  • A player has all 8 cards of one suit.
  • The first bidder has no point card among their first 4 cards.
  • The declarer chooses 7th-card trump but holds no point card in the resulting trump suit.
• Last bidder must bid. After the other three players pass, require the last player to make a bid.
• Minimum bid. Set the minimum opening bid to 14, 15, 16, or 17.

Playing

• Play direction. Choose clockwise or counterclockwise play.
• Initial leader (and bidder). Choose either the dealer or the player after the dealer in the selected play direction. The chosen player bids first and leads the first trick.
• Reveal trump. Reveal trump automatically before the first discard, or ask the player who cannot follow suit whether to reveal it. When asked, the player may decline, and notrump play continues until a player chooses to reveal trump. A player who asks to reveal trump must play a trump card when able.
• Bidder trump lead. Allow the declarer to lead trump anytime, or only after trump has been revealed. If the declarer holds only trump, they may lead it.
• Undertrump allowed. When a trick has already been trumped, allow a player who cannot follow suit to play a trump lower than the highest trump already played. When this option is disabled, the player must beat the highest trump when able, but may discard a nontrump card if unable or unwilling to beat it.

Scoring

• Marriage (pair) bonus. When a player holds both the king and queen of trump when trump is revealed, the required contract is adjusted by 4 card points. A marriage held by the declaring team lowers the requirement by 4; one held by the defenders raises it by 4. The adjusted requirement cannot fall below the minimum bid or exceed the maximum available card points. There is no marriage bonus in notrump.
• Point for last trick. Award 1 card point for capturing the last trick, making the maximum possible score 29 points instead of 28 points.
• Less than half the bid double penalty. Double the contract penalty when the declaring team captures less than half the number of card points bid. This doubles the penalty that would otherwise apply, including a doubled or redoubled contract.
• Bids of 21 or more worth double points. Double the game-point value of a contract with a bid of at least 21.

Game Over

• Game over at. End the game when a team reaches the selected positive or negative score, or after a selected number of hands. In a fixed-hand game, the team with the higher score after the final hand wins; the game may end in a tie.
• Points to game over. Choose ±2, ±3, or ±6 game points.
• Hands to game over. Choose 4, 8, 12, 16, 24, or 32 hands.

Computer Players

NeuralPlay computer players offer 6 levels of play. Level 1 is reasonably easy and good for beginners. Level 3 should be fun for most players. Level 6 is the most challenging.

The computer players use different AI methods depending on the level. For card play, levels 1 and 2 use small Monte Carlo searches built on the rule-based player. They examine only a few possible deals, which keeps these levels suitable for beginners.

For card play, level 3 uses a rule-based AI. Its rules include examples such as "In third seat, do not trump partner's winning card" and "In fourth seat, play just high enough to take the trick when an opponent is winning." These rules provide consistent, logical play.

Levels 4 through 6 use Monte Carlo simulation to determine the best play. The AI deals the unknown cards randomly, tries each legal play, and plays the hand to the end to get a result. This is repeated for many possible deals. The average result for each legal play is computed, and the play with the best average result is chosen.

Levels 4 through 6 differ in how many possible deals they simulate. In general, more simulations produce more accurate estimates and better play. The tradeoff is that more simulations take more time, so level 6 may play more slowly than level 4, depending on the device.

Because levels 4 through 6 do not follow a fixed set of rules, you may observe either surprisingly good plays or odd mistakes that do not appear logical. Overall, our tests show that these levels play better than the rule-based level 3. The randomness also makes the computer players feel more human and less predictable.

If you prefer more consistent, logical, and predictable computer partners or opponents, level 3 may be best.

Whichever level you choose, you may adjust bidding aggressiveness. For individual control, choose Custom, which provides separate settings for North, East, South, and West. For each seat, you may adjust play thinking, bid thinking, and bidding aggressiveness. South's custom settings control the strength of the hints you receive.

We are continuing to research and develop improvements to the computer players.

Frequently Asked Questions

How do I change the hand sorting?

See Settings → Hand Sorting. You can change the rank order and suit order, and choose to alternate red and black suits.

How do I reset my game settings to the defaults?

Go to the main screen and choose Menu → Reset.

What are North, South, East, and West (and N, S, E, and W)?

These are the player positions around the table. You are always South. North is your partner, and West and East are your opponents.

What does "claim" mean?

Claiming means that you or your team expect to take all the remaining tricks. When your hand is clearly high, you may claim to speed up play. The AI checks the claim; if it succeeds, the remaining tricks are awarded and the hand ends.

How do I contact NeuralPlay with suggestions and feedback?

Please contact us at support@neuralplay.com.