	NORTH A6 J75 AKT6 5432
T32 Q9432 KQJ87		K987 QT96 87 AT9
	QJ54 AK8432 J5 6

Dealer: South Vul: Both Teams

West

2N 1
Pass

North

3 2
Pass

East

Pass
Pass

South
1
4

Winning Via Under-Ruffing

1 Unusual Two NoTrump: Both Minors
2 3+ Hearts, limit raise or better
This board rotated to make declarer South: original board number: 4

The defence started clubs and South ruffed the 2nd round.
Declarer cashed the

A and got the bad news about the 4:0 trump division.
A spade finesse lost to East's

K and there seemed to be a destined 4 losers: 1 club, 1 spade and two hearts.

East's spade exit was won in dummy.
Declarer ruffed a club in hand and cashed two more spades.
Two diamonds were cashed and the 2 was led from dummy in this position:

NORTH

J7

2

Q
QJ

QT9

K84

East ruffed with the 9 and declarer under-ruffed.
East was forced to lead away from the QT and North-South collected the vulnerable game.

Regardless of who was on lead in this diagram, East can be allowed to win and be endplayed.

An early determination declarer made was to ruff a 2nd club instead of a diamond in order to reach this diagram.
If instead South had tried to ruff a diamond, East could have ruffed and not been endplayed. Reverse East's diamonds and clubs (3 diamonds and 2 clubs instead of 2 diamonds and 3 clubs) and South's plan would now have failed.
How could South determine whether East was more likely to hold 3 clubs rather than 3 diamonds?
Perhaps West's 2N bid would more likely promise 5:5 shape (

) than 4:6 shape.
If so, then by subtraction from 13, East would more likely have the remainder of those suit's leftover after taking into account declarer's combined holdings also (of diamonds: 13 - West:5 - dummyNorth4 - declarerSouth2 = East2 and of course of clubs: 13 - West:5 - dummyNorth4 - declarerSouth1 = East3
If West hadn't bid 2N, declarer might have reasoned, after finding West had 0 hearts and 3 spades, hence 10 cards in the minors, slightly away from the idea.
Of course, and more importantly than the preceding paragraphs, with East West holding 7 combined diamonds and 8 combined clubs, East figured to be longer in clubs than diamonds.
If on a different East West division of the East West 'assets' West had instead jumped to 3

at first term, vulnerable, declarer should probably consider the idea of pursuing a diamond ruff instead of a 2nd club ruff, contrary to the logic of the previous sentence.