Equal Level Conversion Doubles (abbreviated ELCD on the convention card) is a special kind of takeout double.
Normally, when a takeout doubler follows with his own suit, he is showing a big hand--something like 18+. For example:
North's 2 bid shows a hand too strong for a 1 overcall.
Using ELCD, there is one exception to this principle:
If the takeout doubler's partner bids CLUBS, and then the takeout doubler bids DIAMONDS, he is not promising a big hand. For example:
This conversion of CLUBS to DIAMONDS, when using ELCD, does NOT promise a big hand. It can be a minimum takeout double. Why? What does it show? What is the purpose of this agreement?
The thinking is that when the opponents open 1, and you have a hand such as: A 10 5 4
A J 9 8 7
, it would be nice to try to reach a 4-4 spade fit. Overcalling 2 (or passing), might not get the job done. Playing ELCD, you can double with this hand. If partner bids spades (or diamonds), great. If he picks clubs (you know how partners can be!), you simply convert to diamonds. You are not showing a big hand with diamonds. You are showing a hand that was hoping for spades, but had a backup plan with 5 cards in diamonds.
The downside is that if you really have a big (18+) hand with a diamond 1-suiter and you double and partner bids clubs, you have to do something other than convert to diamonds (he won't expect 18+). This is a small risk and small price to pay, so I recommend using ELCD.
Note: The general idea is that any double of HEARTS or SPADES, followed by a response to the takeout double in clubs, followed by a correction to diamonds, shows the other major (4) and diamonds (5+). It does not show extra strength. Most experts use ELCD.
Last updated: June, 2012