In a brand new partnership, there may be quite a few defensive situations to work out when it comes to signals etc. Other situations work themselves out by sheer logic. It's still nice to see that you're on the same wavelength.
This one come up in t' Onstein against Team Orange's Ricco van Prooijen.
I had xx/AK9x/T987xx/A, white/red at imps and the auction went:
pass - (1S) - 2D - (3D);
pass - (4S) all pass
1S was 5+ and 3D showed 3-card support with invitational or better values. Some may not agree with the overcall, but I wouldn't dream of passing when we easily could have the highest making contract. The fact that the suit is bad is not an issue.
I led the K of hearts, playing Rusinow.
Encouraging 2 from Freddan and 6 from declarer. At this point I don't know if partner has a doubleton (singleton), wanting a ruff, or the queen. No problem, I cashed the ace of clubs, which must be a singleton (no reason otherwise to play it) and checked Frederic's signal. He followed with the 10 which must indicate the queen of hearts as an entry. Low club would indicate a ruffing entry.
I continued with a low heart to partner but it was all in vain as declarer ruffed and claimed.
I had never seen this variation before but as long as logic is used a lot of layouts can be interpreted correctly on-the-fly. We both recognized right away here how the club signal should be used.
We could obviously have gotten another trick with an intial club lead, but that might have given me a nasty guess later on a slightly different layout.