Spades is a partnership trick taking game played over a series of Hands, where spades are always trumps.
The goal for a partnership is to reach 500 points before their opponents.
The game consists of four players in two partnerships.
North and South seats form one partnership (you always play in the South seat in The Spades), while East and West form the other.

At the start of each Hand, the deck is shuffled and 13 cards are dealt face down to each player.
This means the entire standard deck of 52 cards is dealt out, and each player can only see their own cards.

The cards are ranked, from highest to lowest: Ace, King, Queen, Jack, 10, 9, 8, 7, 6, 5, 4, 3, 2.
(There are rule variations that change this order for trumps - see below)

Starting with the player to the right of the dealer, and proceeding clockwise round the table, each player makes a bid.
A bid is the player's chosen target for the number of tricks they hope to make, based on the cards they have and the bids already made by the other players.
This bid can be any value between zero and 13. A bid of zero tricks is called a ”Nil” bid and is a special case when it comes to scoring (see below for more on scoring).
Once all bids have been made, the important values are the combined bids from each partnership.
The partnership has to make the combined bid, rather than individuals making their individual bids (there is one exception below).
For example, if North bids 1 and South bids 5, the combined target for the partnership is 6 tricks.
The way that the partnership makes those tricks does not matter, so North could win 4 tricks and South win 2 tricks and the partnership will still have succeeded.

The one exception is ”Nil” bids. A Nil bid counts as zero towards the combined bid for the partnership as usual.
However any individual who bids Nil, but then wins a trick, receives a 100 point penalty at the end of the Hand.

A special bid called ”Blind Nil” is an option available to any player of a team that is losing by 100 points or more.
This bid works like a normal Nil bid, but must be made before viewing your cards, and the bonuses/penalties are double that of a normal Nil bid.

Once the bids are complete, trick playing starts.
A trick consists of each player playing one card in turn onto the table and whoever plays the highest card wins that trick.
The four cards are then cleared from the table and placed face down next to the winner in order to track number of tricks won.

The first player to play a card in a trick is called the lead player.
Immediately after the bidding, the lead player is the player to the right of the dealer. In future tricks, the lead player is the player who won the previous trick.

The lead player in a trick can play any card in their hand, apart from a spade if no spade has been played before (unless the player has no cards but Spades in their hand).

When a spade is eventually played, Spades are then said to have been ”Broken”, and players from then on are allowed to lead with a spade.
Once a card has been led in the trick, play then proceeds clockwise around the table. The other non-lead players must meet the following rules when playing their card:

• If the player has a card of the same suit to that which was led, they must play a card of that suit (any rank is fine).
  
• If the player does not have a card of the lead suit, they can play any card, including a spade (trump suit).

Once all players have placed a card, and there are four cards on the table, the player with the highest card wins the trick.
The winning card is determined as follows:

• If a Spade (trump) has been played, the highest ranked spade wins the trick.
  
• If no Spade has been played, the highest rank of the lead card suit wins the trick.
  

Play then proceeds onto the next trick, with the previous trick winner playing the lead card.
Once all 13 tricks have been played, and the players have no cards left, the Hand is over and can be scored.

The basic scoring works as follows:

• If a partnership makes as many tricks (or more) as their combined bid, they get 10 x ”Their Combined Bid” points, plus 1 point for each extra trick won beyond that (called over-tricks).
  
• If a partnership fails to make as many tricks as their combined bid, they lose 10 x ”Their Combined Bid” points.

For example, if North/South bid 6 tricks, and actually make 8 tricks, they would score 62 points: (10 x 6) + 2 overtricks.
If North/South bid 6 tricks, but only made 4 tricks, they would lose 60 points.

On top of the basic scoring above, players also receive either bonuses or penalties if Nil bids were made:

• If an individual player makes a Nil bid and makes no tricks, they get a 100 point bonus for the team.
  
• If an individual player makes a Nil bid, but actually makes one or more tricks, they get a 100 point penalty for the team.

(Important: A player who bids Nil does not have their tricks count towards their partner's bid. Therefore the partner of a Nil bid player is on their own, and will have to make all of their tricks by themselves.
If they fail to make the bid, the team receives the regular penalty for missing the bid on top of any bonus or penalty for the separate Nil bid.)

Blind Nil bids work in the same way, but the penalty and bonus is 200, rather than 100.

A tally called ”Bags” is kept for each partnership. This is a tally of the number of overtricks made on successful bids.
So, for example, if North/South bid 6 but make 9 tricks, they will get a score of 63, but also add 3 to their ”Bags” tally for the extra tricks they made over their bid.
Bags are bad for a partnership and are there to penalize underbidding. However, a points penalty is only applied to the team when the Bags tally reaches or passes 10.
At that point the partnership takes a penalty of 100 points, and the number of bags is reduced by 10.

For example, North/South have 9 bags, but the current Hand has just ended and they have made 3 overtricks (they bid 5, but made 8 tricks).
This means 3 is added to the number of bags, taking them to 12. Therefore North/South take a 100 point penalty, and the number of Bags is reduced back to 2.

The game continues with new Hands until one, or both, partnerships reach or pass 500 points. The first partnership to do this wins the game.
If both teams do this at the same time, the partnership with the most points wins.

This app allows the following rule variants:

(1) Play To

This allows you to choose to play to 300 or 500 points or to a limit of 8 or 16 hands.

(2) 10 Bag Penalty

This determines the number of penalty points for every 10 bags collected. Can be 100 or None.

(3) Overtrick Points (bags)

This allows the immediate credit per overtrick/bag to be 1, 0 or -1.

(4) Blind Nil Available

This option determines when Blind Nil is allowed. For example if "200 Pts" is selected then you need to be 200 points behind before you are allowed to go Blind Nil.

(5) Card Passing

This setting allows a single card to be passed between partners when either player tries a Blind Nil.
This can make it easier to succeed with a Blind Nil bid.

(6) Nil/Blind Nil Bonus

This allows you to choose the number of points awarded for successful Nil/Blind Nil bids. The same number of points are also deducted if such a bid fails.

(7) Trumps

There are 5 different trump settings, each one providing a slightly different set of cards to be used as trumps.
This allows you to customize the game to how you’re used to playing, or to try something new.

Spades are always trumps, with settings adding other cards to the trump suit. The added trumps are always considered Spades for the sake of following suit, leading, and other rules.

The different Trump modes are:

Normal:

This is the default setting. Only the Spades are trumps, with Ace high.

New York City (Based on Christian A.Baxter rules):

In this mode, the Jokers are added (The 2♣ and 2♥ are removed from the deck).
Red/Large Joker is top trump, followed by Black/Small Joker, 2♦ , 2♠, and then the rest of the Spades with Ace high.

Barmore (Based on Dennis J Barmore's rules):

This is the same as New York City above, but 2♦ is not a trump.

Deuces:

In this mode, the 2 of each suit (Deuces) are the top trumps. The top trump is 2♠, followed by 2♦, 2♣ , 2♥ and then the rest of the Spades with Ace high.

Jokers:

This simply makes the Jokers the top trumps (Red/Large Joker highest), followed by the Spades with Ace high. 2♥ and 2♣ are removed from the deck.