Five Hundred Help

Help is organized in the following sections.

• Five Hundred Rules
• Preset Game Rules
• Learning Features
• Rule Options
• Computer Players
• Frequently Asked Questions

Five Hundred Rules

These are the standard NeuralPlay Five Hundred rules. You may customize the rules to your liking as described here.

Five Hundred is a 4 player partnership game played with a deck of 43 playing cards. The deck consists of 10 spades (5 to ace), 10 clubs (5 to ace), 11 hearts (4 to ace), 11 diamonds (4 to ace), and one joker.

The play is broken down into hands. Hands are played until the game is over. You form a team with the player across from you and accumulate points from each hand played. The game ends when a team reaches plus or minus 500 points. The team with the highest score wins.

Each hand consists of five stages: dealing, bidding, kitty exchange, playing, and scoring.

Dealing

At the start of the game the dealer is chosen randomly. From then on, the deal rotates clockwise until the game ends. The cards are dealt face down to the four players and the kitty, giving each player 10 cards, and the kitty 3 cards.

Bidding

The bidding begins with the player to the left of the dealer. The bidding rotates clockwise. A player may choose to bid or pass. Once a player has passed the player may not bid again.

A bid consists of a level from 6 to 10 and an indication of the trump suit or notrump (no trump suit). The level determines the number of tricks the bidder's team will take during play.

A bid must be higher than any previous bid (the bid ranking is defined below). If all players choose to pass is 'passed out'. The hand is not played and no points are awarded for the hand. A new hand is dealt.

The ranking of the bids is determined by the level and the trump suit. First, the higher level outranks the lower level. Next, for a given level the trump suit order from low to high is: spades, clubs, diamonds, hearts, and notrump.

Some examples will help. A bid of 7♥ is higher than 6♥. A bid of 6♣ is higher than 6♠. 6NT (6 notrump) is higher than all other 6 level bids.

The bidding finishes when three players have passed. The player with the highest bid wins the bidding. This player is called the declarer. The final bid determines the contract. Here are some example contracts.

• 7♥ - the declarer's team must take at least 7 tricks, hearts are trump.
• 8NT - the declarer's team must take at least 8 tricks, there is no trump suit.

There are two special bids: nullo and open nullo. Nullo is played as a notrump contract and indicates that the bidder will take no tricks. Also, the nullo declarer will play without a partner to help during play. Open nullo is like nullo, except that the bidder's cards are exposed to the opponents during play. Nullo ranks between level 7 and level 8. Open nullo ranks between 10♥ and 10NT.

Kitty exchange

After the contract is determined the declarer takes the 3 cards from the kitty and discards 3 cards back to the kitty. The kitty cards taken and returned are not exposed to other players.

Play

The play consists of 10 tricks. A trick consist of 4 cards, 1 card from each player. For each trick, there is a leader, a suit led, and a winner. The leader is the player who plays the first card. The suit led is the suit of the card played by the leader (if a joker is led during play of a notrump contract, the player chooses the suit led). The winner of the trick is determined by the best card played of the suit led, however, if a trump was played on the trick, then the winner is the best trump card played.

The best card in a given suit is determined by the contract being played. For suit contracts the joker becomes the highest trump, followed by the jack of the trump suit, the jack of the suit of the same color as the trump suit, and then the other cards of the trump suit. The card rankings are as follows.

• Suit contracts: 4, 5, 6, 7, 8, 9, T, Q, K, A, Jack of same color, Jack of suit, Joker
• Notrump contracts: 4, 5, 6, 7, 8, 9, T, J, Q, K, A.

In notrump contracts, the joker is the highest rank. When led, the leader declares the suit, others must follow and the joker will win the trick. The joker can be played on a trick when one does not have the suit led. The joker will win the trick (like a trump).

The declarer makes the first lead and may lead any card. Play continues clockwise to the left with each player playing a card in turn. Players must play the suit led if they have it otherwise, they may play any card from their hand.

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 the hand has been played out, the number of tricks taken by the declarer's team is checked against the contract bid. For non-nullo bids, the declarer's team needs to take at least as many tricks as the level bid to make the contract. If the team makes the contract value is added to their score. If they fail, the contract value is subtracted from their score. The defenders receive 10 points per trick captured. The contract value is determined by the following table.

There is one exception to the above scoring rules. If the declaring team takes all the tricks, it is called a slam. The team is given a minimum of 250 points for the slam. If the bid was 8♠ or less the resulting score is higher than the table score. If the bid was higher than 8♠ the table score is applied.

The bid of nullo is worth 250 points. If the declarer succeeds in taking no tricks, 250 points are added to the teams score. If the declarer fails, 250 points are subtracted. In any case, the defending team will receive 0 points.

The bid of open nullo is worth 500 points. Except for the point difference, it is scored just like the nullo bid.

After the scores for this hand are determined, the hand scores are added to the total game scores. The game ends when one team reaches plus or minus 500 points.

Web links

There are many helpful web sites discussing Five Hundred. Here are a few we found helpful.

• Wikipedia
• Pagat.com

Preset Game Rules

Five Hundred can be played with many different rule options. We have included some preset rules to show some of the variety. See Rule Options to customize the rules.

• Australian. These rules are the NeuralPlay default rules described above.
• Australian (no nullo). These rules are the rules described above except to keep it simple, nullo and open nullo bids are not allowed.
• American. These rules are based on the NeuralPlay rules described above. The exceptions are that there is only a single round of bidding (each player may bid only once) and the 6-level bids are 'inkle' bids. Inkle bids hints describing one's hand to partner, for details see Rule Options.
• Canadian. These rules are based on the NeuralPlay rules described above. The exceptions are as follows. Play is with 6-card kitty and a 46-card deck with all 4's and 2 jokers. The bidding starts at the 7-level. The defenders do not receive points for tricks taken during play. Instead, they receive the bid points if they set the declarer. The game ends at 1000 points, the defending team may win. Open nullo is permitted however, nullo bids are not permitted.
• American (double nullo). These rules are based on the American style rules mentioned above. The double nullo bid has been added (500 points). Double nullo may be bid only after partner has bid either nullo or open nullo. Open nullo and nullo may be bid anytime. The open nullo bid is valued 350 points and nullo is valued at 250 points. There is a 5-card kitty.

Learning Features

NeuralPlay Five Hundred offers many features to help you learn and improve your play. These features may be enabled, disabled, and/or adjusted in settings. The features include the following.

• Hints. By default the AI will show you a hint when you ask for one. In settings, you may ask the AI to always show you a hint. Or, you may ask the AI to check your bid or play and show you a hint only when it differs from yours.
• AI points estimate. When enabled, the AI will show an estimate of the number of points that will be scored for each legal play. This is an estimate of the expected value of each legal play, averaged across many simulation results. Note that the AI suggested play may not be the estimate resulting the most points or the play suggested by the AI. This may be due to strategic considerations or noise.
• Card counter. When enabled, a card counter of the cards that have been played during play will be shown.
• Analyze bid. When enabled, an "Analyze" button will be shown during the bidding. Tap the button and enter a bid to get an estimate of the chance of the bid making. See settings to enable.

Rule Options

Play with the Five Hundred rules you like! NeuralPlay's Five Hundred offers many rule options for you to customize the game to your liking. Preset rules include defaults for the American, Australian, and Canadian variants. You can further customize them with many options, including the following.

Dealing

• Kitty size (deck size). Choose from 1 to 6 cards for the kitty. The deck size will be adjusted accordingly.
  • 1 card. Removes the 4♥ and 4♦ to make a 41 card deck.
  • 2 cards. Removes the joker to make a 42 card deck.
  • 3 cards. The standard 43 card deck.
  • 4 cards. Adds the 4♣ to make a 44 card deck.
  • 5 cards. Adds the 4♣ and the 4♠ to make a 45 card deck.
  • 6 cards. Adds the 4♣, the 4♠, and the black joker to make a 46 card deck (the black joker is the highest joker).
• Highest joker in the kitty. Choose to place the highest joker in the kitty. Notrump bids become easier to make.

Bidding

• Bidding rounds. Choose between multiple rounds (Australian 500) and a single round (American 500).
• Minimum bid. Bids start at the 6 level by default. You may choose to start at the 7 or 8 level. This may be particular useful for variants that use a 6-card kitty and/or place the high joker in the kitty.
• Inkle bids. When selected, bids at the 6 level can be made only by the first 2 players to bid. These bids are called 'inkle' bids and suggest strength in the suit to partner. Inkle bids cannot win the bidding. If the bidding does not reach the 7 level the hand is considered passed out. Inkle bids are used in American 500.
• 6NT shows a joker. Enable to use 6NT as a conventional bid to show a joker.
• Nullo bids. Choose whether nullo bids can be made anytime, after a bid of 7, or not at all.
• Open nullo bids. Choose whether open nullo bids can be made anytime, after a bid of 7, after a bid of 8, or not at all.
• Double nullo bids. Choose whether double nullo bids can be made anytime, only after partner's nullo or open nullo bid, or not at all.
• Nullo ranking. Choose how the nullo bid is ranked among the other bids: either based on the point value or fixed between the 7 and 8 bids.
• Open nullo ranking. Choose how the open nullo bid is ranked among the other bids. First it is ranked based on point value. This setting determines what happens when there is a tie, open nullo can be above, below, or equal to the other bid of equal value. When the open nullo value is 430 the rank will be between 9 and 10 bids. When ties are set to rank open nullo above the other bid and open nullo value is set to 520, the open nullo bid will the highest ranking bid. When ties are set to rank open nullo equal to the other bid, the first bid to be made takes precedence.
• Nullo and open nullo bids receive kitty. Choose whether or not nullo and open nullo bids get the benefit of receiving the kitty.
• Stick the dealer. When enabled, deals may not be passed out. If all other players have passed, the dealer cannot pass.
• Raise one's own bid. Choose whether or not after all players have passed the winning bidder may raise or change the bid.
• Reentering the bidding. After one has passed, one may or may be allowed to reenter the bidding. When the raise one's own bid option is enabled, you may choose to allow reentering only on after a change of the bid suit/notrump, a change of level only does not allow reentering.
• Notrump contracts. Choose to play standard aces high notrump, the J5 variant where the jacks of each suit are high, or disable notrump bids. Note that the J5 variant does not apply to nullo hands, when playing nullo or open nullo the jacks do not become high in each suit.
• Misdeal. Optionally allow a player to declare a misdeal when dealt a hand with no aces and no faces. The hand will be redealt by the same dealer.

Playing

• Initial leader. Choose whether the declarer leads first or the player to the left of the dealer.
• Joker leading during notrump/nullo contracts. Choose when/how a joker may be led: choose any suit; choose a not yet led suit; choose a not yet shown void suit; or can only be led on the last trick.
• Joker following during notrump/nullo contracts. Choose whether the joker may be played anytime when following (not leading), played only when void in the suit led, or must be played as either the first time the suit is led or last card of the suit led (as soon as one runs out of the suit).
• Joker following during nullo contracts. Choose either: may play when void or must play when void.
• Finish hand early when determined. When the points are determined the hand will end early, remaining tricks will not be played. Can be useful to speed up nullo contracts when the bidder takes a trick and the points for the hand are determined.
• Nullo claims are for no tricks. When enabled, claims by the nullo and the open nullo declarers are for 0 tricks. When not checked, the nullo player claims are for all the remaining tricks. This options can be enabled to speed up nullo play as most likely the nullo player will be taking no tricks. Note, this option does not apply to double nullo contracts.

Scoring

• Scoring system. Choose from three different scoring systems for the bid score values.

  Avondale (default)

  Level	Spades	Clubs	Diamonds	Hearts	Notrump
  6	40	60	80	100	120
  7	140	160	180	200	220
  8	240	260	280	300	320
  9	340	360	380	400	420
  10	440	460	480	500	520

  Original

  Level	Spades	Clubs	Diamonds	Hearts	Notrump
  6	40	60	80	100	120
  7	80	120	160	200	240
  8	120	180	240	300	360
  9	160	240	320	400	480
  10	200	300	400	500	600

  Perfect

  Level	Spades	Clubs	Diamonds	Hearts	Notrump
  6	20	40	60	80	100
  7	120	140	160	180	200
  8	220	240	260	280	300
  9	320	340	360	380	400
  10	420	440	460	480	500

• Nullo value. Choose the value to be 150, 210, 230, or 250 points. The rank of the nullo bid among the other bids may be adjusted by the nullo rank setting.
• Open nullo value. Choose the value to be 250, 330, 430, 500, or 520. The rank of the open nullo bid is adjusted according to the open nullo rank setting.
• Double nullo value. Choose the value to be 500, 510, or 520. The rank of the double nullo bid is adjusted according to the open nullo rank setting.
• Slam. Choose whether or not taking all the tricks (slam) is worth a minimum of 250 points.
• Defender scoring. Choose whether or not the defenders get 10 points per trick captured. And optionally, 10 points per trick declarer captures during nullo contracts.
• When set. When the contract is set, choose whether the declarer receives minus the bid points or the defenders receive the bid points.

Game over

• Game over. Choose whether the game ends at a predetermined number of points or after a certain number of hands.
• On reaching game over, choose how the winners are determined. Options include: highest score wins, capping the defenders score at 490 or 460; must bid (and make) to win.

Computer Players

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

The AI bots employ different AI methods depending on the level. Levels 1 and 2 use simple methods to provide an introduction to beginners. We will not describe them in detail here.

Level 3 uses a rule-based AI. The AI consists of rules such as: "In 3rd seat, do not trump partner's high card" and "In 4th seat, play just high enough to take it when an opponent is winning", etc. We find the rules work quite well and can provide good play.

Levels 4+ use Monte Carlo Simulation to determine the best play. Basically, the AI will deal out the unknown cards randomly. The AI will then try each legal play and play the deal to the end to get a result. This is repeated for many deals of the unknown cards. The average result for each legal play is computed and the legal play with the best average result is chosen.

Levels 4+ differ in how many times the unknown cards are dealt out. In general, the more deals the more accurate the simulation. This results in better quality plays. The trade-off is that more deals take more time, play may be slower on level 6 than level 4 depending on the device.

Since levels 4+ do not use rules, you may observe either surprisingly good plays or odd mistakes that may seem not to follow any logical rules. Overall, our tests show that the levels are better than the rule-based level 3. We also find the randomness makes the computer feel a bit more human-like and fun.

If you prefer a more consistent, logical, and predictable partner AI and/or opponent AI, then level 3 may be best.

We are continuing to research improvements and new computer AI algorithms. We continue to update the bots as we develop improved algorithms.

Frequently Asked Questions

How do I change the hand sorting?

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

How do I reset my game settings back to the original game settings?

Go to the Main Screen and choose Menu -> Reset.

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

These terms are used in bridge games. You are always South and your partner is always North. The terms You and South are used interchangeably.

What does claim mean?

Claim means you will take the remaining tricks. When your hand is clearly high, you may claim the remaining tricks to speed up play. If the claim is successful (the AI will check), you will receive the remaining tricks and the hand will end.

How do I contact NeuralPlay with suggestions and feedback?

Please contact us at support@neuralplay.com.