This auction can create some problems for the intervening side. A suggestion for dealing with them follows.

The late Gabino Cintra, a World Pairs champion (playing with Marcelo Branco) from Brazil, liked to wax poetical about the everlasting battle between spades and hearts. He was a frequent vugraph commentator from Brazilian and South American events, and he would have enjoyed the following board greatly.
Board 2 from the World Youth Teams Championships finals was yet another skirmish between the two ancient opponents.

Let’s take a tour through the tables where these cards were on display and see if there is something to be learned from the auctions.Examining the four hands in the quiet environment of our screens, we can see that NS will make 11 tricks in hearts; and that EW have a profitable sacrifice in 5S, paying only 300 in doubled undertricks. But things are never as clear as that when you are looking at only ¼ of the deck, in an important match.

U-26 Open (Singapore vs. Sweden):

A nice looking hand. When Adam Stokka from Sweden held this hand, his partner passed and RHO opened 1 Heart.
What would you do? Most people would probably bid a simple 2 Diamonds, but I think a case can be made (facing a passed partner, and vul vs. non-vul) for the 3 Diamonds overcall.
Would it have made any difference? Perhaps, for this was the full hand:

After the first bid by West, the bids were all pretty much forced. I would not say that East could never pass 2 Diamonds with that hand, but I can say that I would never do it. And the final result was 500 for Singapore, when EW lost the obvious 6 tricks (2 hearts, 3 diamonds, 1 club), due to the spade blockage which prevented the King of spades from adding any trick to declarer’s total.
After an initial 3 Diamonds overcall, North would not have a natural penalty double.
Would South reopen? He should, but there is no doubt that it is easier for North to double 3 Diamonds than for South to do it.
Meanwhile, in the other room, the Singaporean pair nimbly avoided any trouble in the bidding with these cards:

There are lots of little things going on in hands like this that explain the big swing. In this auction, the first component is East’s light opening (in a Precision context), even vul vs. non-vul. Many people refrain from light openings because they are, allegedly, risky. But any coin has two sides: sometimes a light opening helps you avoid trouble.

This is not enough to explain EW’s escape, though: full marks must also be given to Jazlene Ong’s restraint with the West cards (and again, the light opening context of Precision helped a lot there). The “death holding” of xxx in the opponent’s suit, the blocking SA, the weak (even if very long) suit, were all warning signs that were duly noted. (I speak here as someone who would have a great deal of difficulty in finding this pass).

Curiously, though, the bidding success was followed by a trick lost in defense, enabling N-S to go plus in their 2H contract. The Ace of Spades was led, and West then shifted to a club; King of spades (club pitch), spade ruff, dA, and now, when West played a diamond, East did not really believe that his partner had passed with a 7-card suit headed by the AJ and a side Ace, and so ruffed small! Ida Grönkvist gratefully overruffed cheaply, drew trumps, and made 8 tricks.
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But Singapore accepted the 9 IMPs (rather than the 11 they might have gotten if East had ruffed high).