I ran into an interesting problem in a sequence last Thursday night. The most interesting part for me was the reminder of the assumption problem.
What I mean by this is that there are sequences where at some point you or partner makes a bid that is the assumption bid. The bidder may think that the bid shows X, but the partner may think the bid shows Y. Or, perhaps partner is uncertain as to whether the bid shows X or Y and is therefore stuck.
Now, we all know to avoid, if we can, a call that is unclear, but the assumption bid is a call where one partner thinks it is clear and therefore does not recognize that partner can have a problem. An assumption bid can result in arguments when bidder and partner both think the bid has a specific meaning, different from each other, not recognizing the alternative.
The example was 2C-P-2D(GF)-P-2S-P-3NT. Is Responder showing a tweener hand (8-9 or so), kind of a Baby Quantitative, or is this Fast Arrival (2344 with two queens)? Either is perfectly playable, reasonable, and logical.
On the one hand, you might have a thought as to what this should be, or maybe a thought that a conventional or artificial meaning might make sense. My point, however, is that this actual sequence involved an assumption bid at the table. The person bidding 2NT had an assumed meaning, whereas Opener did not know and recognized the problem with interpretation.
I think one skill at this game is in recognizing "assumption bid" situations. Places where discussion is unlikely but where general principles could lead to a combination of results. This skill allows you to better discuss sequences (getting deeper into esoterica, perhaps). It also allows you to track a regular partner's thinking, such that you can predict his interpretation better in these assumption bidding situations. It allows you to avoid assumption bid options in favor of perhaps inferior but safer non-assumption options. It allows you to better structure your own calls to exhibit consistency as to assumption bid situations ("bid where you live," "flags rather than cues," "shortness third"). If you can sing a jingle after the assumption bid call you elect, that's a good thing.
If you can spot assumption bid situations, this will allow you to track partner (if he goes there). If you find that partner has a consistent track, you are that much better as a partnership. If, on the other hand, partner seems to run wild across the field, apparently inconsistent in his interpretation of assumption bid resolution, then perhaps ask him his thoughts as to why Call A showed X but Call B showed Y. Maybe he concedes inconsistency and corrects it. Maybe he explains a nuance that you missed, clearing up the inconsistency as actually consistent for a deeper reason, and you either grow or realize that he is way out there. Maybe he stares at you with a dumb look, calls you an idiot, and displays his own ignorance, in which case you run like a deer for the woods, finding a new partner.
If you find assumption bids hard to spot, I can make it easy for you, as a starter. I bet you and partner reach points where a bidding misunderstanding occurs or where a really bad call seems to have been made. Someone might have been an idiot, or you both may have been fools. Or, this may be a situation where one or more assumption bids occurred -- two people can bid intelligently to a ridiculous contract because they made sane but ionconsistent-with-each-other assumption bids. So, if partner seems to have bid something screwy, stop. Don't write this off as insanity. Grab this opportunity as a case study in assumption bids and figure out where the assumption bid(s) is/are hidden, figure out the reasoning behind them, and learn from the situation. Maybe your "obvious call" was an assumption bid or was based on a different interpretation of an assumption bid by partner.