There are so many different variations in the game of Spades that the rules have to be made clear each time a new group of players gets together. Bidding is one of the most variable of all the rules in the game, so here are some of the more popular bidding versions.
Any number of players can play, either individually or in partnered teams. Each team must bid at least four tricks, so if one member bids Nil, it leaves it up to the partner to bid at least four.
When playing individually, a player can only bid Nil, Board (the 4-trick minimum) or any number above Board. Some players prefer to set Board to a different number of tricks, which changes strategies within the game.
One of the greatest differences in some forms of Spades is how partners are allowed to converse with each other during the bidding process. It is always good to cover this prior to the start of the game.
When partners discuss the cumulative number of tricks, they come up with a total they both feel comfortable with, but the team that bids first somewhat lets the other team get an idea of what they have in Spades and high cards.
The team that does not deal bids first. Even though one team bids a set number of tricks, it does not mean that the other team will need to bid an amount that will total 13 tricks between both teams.
For instance, both teams can bid 7 tricks; but one team will be set because there are only 13 tricks total in the game.
In partnership bidding, teammates cannot give specifics as to what is in their hand. There is no discussion to how many of any suit a player is holding or how many high cards they have. Breaking the rules in discussion results in a misdeal and, according to the rules of the house, penalty points may be assessed.
One exception used in information given during the bidding round is that a player with three or more aces can use the phrase "Ace Check" to let his partner know. Of course, this also reveals the same information to the opposing team. Ace Check is most often used in games where deuces are high or other trump variables are set that give other cards a higher rank than the Ace of Spades.
In this variation of Spades, the first bidder must bid a minimum of six tricks. Remaining bidders must raise or pass. After passing, a player cannot bid again. The partnership that wins the contract must make their bid. The defending partnership can either set the team with the contract, or they can play to make them win more tricks than they bid.
The contracted team loses 10 points for every bid trick they do not take, and they get no points for overtricks. They score 10 points for each trick if they make their bid. Their opponent (defending team) is given one point for every trick they win and 10 points for every trick the contract team takes over their bid. You can see the strategy potential of this game in that the defending team can end up earning more points than the contract team if they "play their cards right."
These are just a few of many various bidding options in the game of Spades. Changing the game a little makes it more interesting and it's a lot of fun as long as all participants know the specifics before game play begins.