Gronbog and I were trying to debug a thorny problem that revolved around a rather interesting play. You're playing double deck, S17. In this entire discussion, we're considering only basic strategy; the notion of counting is not involved. You're dealt A,7 vs. the dealer's ace. What's the correct play? You may know that it's to hit. From a fresh deck, this time, you get A,4,3 vs. A. Now what? Well, if you consult the standard, run-of-the-mill BS cards, you will be told to hit your "soft 18" (I loathe the term, but no choice but to use it here). Only that's wrong. If you consult my book or my BS cards, you will see a split box, where the right side shows to hit the two-card holding of A,7 but to stand on the multi-card A,7, or soft 18 (S18), if you must call it by that hideous name.

Fine. So here's where the plot thickens. Suppose I tell you that you have, forgive me, soft 18, but I don't disclose whether it's the two-card variety of the multi-card holding. NOW what? You tell me that there's really no practical value to this discussion, because you'll always see your hand and you'll always know which it is. But a) trust me when I tell you that this was the source of four days of aggravation between Gronbog and me, trying to debug a problem with our research project, and b) suppose I offered you a million dollars for answering the question correctly. THEN would you care?!

So, it turns out that the correct answer is to stand. And the reason I titled this post, "A unique play in all of blackjack," is because it is the ONLY play in all of blackjack (any number of decks, any rules), where the multi-card BS play is superior to the two-card BS play. You're probably quite familiar with the other way around, involving 16 vs. T. You probably know that your two-card 16 should always be hit, but that, on average, over all multi-card holdings, standing is better. But, it's also true that when taken as one single play--generic 16 vs. T--hitting is the proper choice; i.e., the multi-card strategy is the WRONG play.

So, once again, soft 18 vs. A in DD, S17 is the only play in all of blackjack where the multi-card BS (to stand) is superior to the two-card (A,7) strategy to hit, if you don't know which of the two you're holding. And, I suppose, the point is that this information is not so readily available or widespread.

Don