In bridge, how do you tell when to use holdup versus blocking plays?

Question

You are the declarer at a 3NT contract (1NT, 3NT, no opposing bids). West leads what appears to be a five card suit, and you have Axx in dummy.

Your main concern is that East can get the setting trick by attacking a vulnerable tenace you have in hand; something like Jxx in the led suit, or AQx in a side suit (and maybe the the answer to the question below is found in the difference between one and the other).

At times, you should go up with the ace in dummy (if East has an honor and a small card) to "block" the suit. At other times, you should hold up the ace until the third round to exhaust East of the led suit. How do you tell the difference?

A club kibitzer gave the opinion, "You use a blocking play if you're worried about what will happen in the LED suit (e.g. if your tenace is Jxx, above), and you use a holdup play when you're worried about what will happen in a different suit (e.g, your AQx tenace)." Is there any truth to this statement?

I haven't stated whether West led from "top of a sequence" or "fourth best," but maybe the answer to question lies in the difference between the two.

Because another take of this matter is "avoidance." That is, if the priority is to keep East off lead, then let West win if he led a high card, and cover if West led fourth best, to prevent East from getting the lead.

I have been told that if I have something like Axx in hand opposite xx in dummy, I should hold up, and hope to exhaust East of the suit. But if I have Axx opposite xxx, West led the queen (denying the king), and East plays low, I might take the trick to "block" the king in East. Does this make sense?

Answer 1

To prevent the lead form RHO through your tenace, you want to win the ace when RHO plays his last card in the suit. If it looks like LHO has 5 cards, with three in dummy and your hand, win the second round with the ace. If you have only two in had with three in dummy, win the third round with the ace.

In regards your Club Kibitzer - yes, the proffered advice is in general sound - however, the cardinal rule is always Count the hand. If you have counted the hand, the answer is often obvious and possibly counter-intuitive from the general rule suggested by heuristic analysis.

Answer 2

There is a little known rule in Bridge called "The rule of 11" that tells you how many cards your right-hand opponent has that are higher than the one led.

If your LHO has not lead an honour card then they are likely to be missing one of them - they would lead one from a sequence or internal sequence. In this case it is likely that their partner has one honour. if you can deduce that the player has HX then you can try and block the suit by going up with your Ace. I would look out for 6-card combinations when you hold the Ace and Ten.

With regard to hold-up plays, the first thing to do is to see whether by holding up you can prevent the defence from being able to communicate with the 'danger hand' - the one whose card holding may cause you to fail in your contract - in the suit led. Even if they may hold an entry in another suit, holding up to prevent (or at least reduce the chance of) this happening will be worthwhile. There may also be occasions when you can hope that the partner has a singleton honour, but the opening leader will have an entry. In which case you might duck even with a finessable honour combination from your right, but safe from attack from the left.

Of course you should also take time to work out whether the opponents (having taken the trick by you holding up) have a possible damaging switch.