pescetom, on 2020-January-20, 14:18, said:
Not sure I follow you here. My partner knowing that double of 1♥ shows 4-card ♠ would do just that with with 4=2=5=2, not bid 2♦ which suggests more diamonds or less spades.
I don't think most players would agree that 2
♦ shows any more than 5 diamonds. Of course, you may have more. But, typically, 5 is the minimum number.
The problem with doubling is when you catch your partner holding a bad 3235 hand. Or worse, a bad 3325 hand. Now what? Takeout doubles show 3 cards in each unbid suit. If you don't have that shape, don't bid them. It's just bad bridge. If you have a strong hand, this is a different story, but, then it's not really a takeout double is it? It just looks like one. If I had to pick one rather garbage agreement that novice players should correct before any other, it would be offshape doubles such as this example. At least, without any set of agreements around them that facilitates them. I won't dismiss them entirely without applying context.
If your partner can't make a balancing double themselves, or cannot balance with an unbid suit, how effective is this takeout double with such a hand really going to be? Now, how often are you going to run into a train-wreck doubling without clubs? Am I really gaining enough on average to risk a bad board? Possibly, but, I'll erode partnership trust in the process. It's just not worth it.
If I had 4162 shape, I certainly would not double. So, not doubling doesn't deny 4 spades. So, I'm not just going to randomly double with all hands that have 4 spades. If I don't trust partner to balance, then I'm bidding 2
♦ with 4252 shape, if I do, then I'm passing. Depending on the suits and my strength of course.