In the game of Spades, what is the best or popular practice to bid the ♠ suit? That is to say, how to estimate the number of tricks my spades suit can take?

I calculate my takes in the spades suit by considering those three factors:

1. High spades - {A,Kx,Qxx,Jxxx} where x are spades cards used as protection.
2. Long spades suit - count each spade beyond the 4th, some count the 4th spade as a "half a take" which combined with other factors might be a take.
3. Short sides suits + spare spades
• Void and 1/2/3 spare spades is 1/~1.5/~2.25 takes.
• Singleton and 1/2 spare spades is ~1/~1.5 takes.
• Doubleton and 1 spare spade is a bit less than 1 take.

Note: do not count the same card twice. Each card should be count once where it produce the maximal value.

• What do you mean by "is a take"? Also, since half cards don't exist, please expand on how you calculate the net of actual spades in excess of 3.5. Sep 3, 2018 at 11:11
• "is a take" means count this card as a take (increase your bid by 1). I count the forth spade as a half a take, so If I also have other "half" takes such as side suit queens or side suits doubletons it will sum up to a take. Sep 3, 2018 at 11:20
• Great! That would be worthwhile to add to the question. Sep 3, 2018 at 11:22

Your method of adding [Spade-Length] - 3.5 seems reasonable, except I would halve that whenever partner has already made a bid of 4 or higher. Any bid in excess of 3 is very likely to include Spade length, and it is desirable to avoid double-counting that asset.

Even when partner's bid above 3 is solely based on high card strength, that reduces the value of extra Spades in your own hand as you will be attempting to not ruff those assets.

Also, I believe a refinement of the Spades' tricks estimate should consider the presence or absence of a void/singleton in one's hand. Balanced holdings around the table reduce the likelihood of ruffing tricks, while unbalanced holdings increase their likelihood. I'm not yet sure how I would do that.

Here is a table of all the hand pattern probabilities, with the top few (covering nearly 85% of possibilities) excerpted below.

Note that the 4333 pattern is only the fifth most common hand pattern, and the most common is 4432 at over 21%. If we take the 4432 pattern as standard, then we can rank the most common patterns as being either stronger or weaker than the standard (in ascending order of estimated strength:

• Distinctly Weaker: Estimates from Contract Bridge analysis suggest at east 0.25 trick weaker
• 4333 HPS = 2(4-5) + (3-3) = -2
• Standard:
• 4432 HPS = 2(4-5) + (4-2) = 0
• 5332 HPS = 2(5-5) + (3-2) = 1
• Stronger: Estimates from Bridge analysis suggests at least 0.25 tricks stronger than average
• 5422 HPS = 2(5-5) + (4-2) = 2
• 6322 HPS = 2(6-5) + (3-2) = 3
• 5431 HPS = 2(5-5) + (4-1) = 3
• Distinctly Stronger: Estimates from Bridge analysis suggest at least 0.5 tricks stronger than average.
• 6331 HPS = 2(6-5) + (3-1) = 4
• 6421 HPS = 2(6-5) + (4-1) = 5

In this context stronger should be interpreted as more capable of implementing the desired strategy. A 6421 hand with short Spades and all its high cards, even if Aces, in the two long suits might be very capable of successfully bidding Nil. Obviously the placement of a hand's high cards is of import as well, as an additional refinement.

Also, these estimates are a priori - before trumps have been established. Clearly a long trump holding (Spades playing Spades) is even more valuable than shown here for winning tricks - but is less able to lose tricks.

One numerical estimate of Hand Pattern Strength would be to take double the excess of the length of the longest suit over 5, plus the excess of the second longest suit over the shortest suit. I have marked this value as HPS for the hand patterns above.

My first attempt at a comprehensive hand evaluation for Spades would be the sum of:

That could be further refined, with experience, by adjusting the denominators for the second and third components for HPS and Spades length. When contemplating a Nil bid, consider subtracting the HPS term instead of adding it to the sum.

• Halving could result in 1/4 bids, which surely don't exist! Sep 3, 2018 at 16:58
• @TheChaz2.0: It's called rounding. The 4th and 5th cards ( (0.5 + 1.0) / 2 ) become an estimated trick, as do the 6th and 7th ( (1 + 1) / 2 ) when both held. Sep 3, 2018 at 21:02