NORTH  A54  AK32  A832  AK  KQJ6  J4  KJ54  QJ5    987  8765  6  T9876    T32  QT9  QT97  432

Dealer: West    Vul: None   MP Scoring West 1 1 Pass North X 4 East Pass Pass South 1 Pass

In retrospect, the 2 alternative was to be preferred, tending to deny more than 3 of either major.
North not unexpectedly jumped to the heart game contract.

The K lead was won in dummy and South took stock.
North-South assets were a combined 6 spades, 7 hearts, 8 diamonds and 5 clubs, not to mention 22 HCP in dummy and 4 HCP in hand: 26HCP.

Given West could have no more than the remaining 14 HCP and bid a 2nd time, introducing a new suit, opposite a passed partner, South expected at least 4 spades and at least 5 diamonds.
That left 4 other cards at most in hearts and clubs.
With 8 outstanding clubs and 6 outstanding hearts, East would have at least 10 cards in those two suits.
How West's "at most" 4 cards outside spades and clubs divide?
Declarer decided that West most likely held no more than 2 hearts - perhaps even a void.
East then would have at least 4 hearts. On which side would the J be? In the hand with at most 2 cards in the suit? In the hand with at least 4 cards in the suit?
Would that 1 HCP of a J be a requisite for an opening hand?
Would a Jx really be counted as a point in bidding a 2nd time opposite a partner that passed?
Declarer led from dummy towards the T at trick two, losing to West's J.
West cashed the KQ and exited a small club.
Declarer drew two more trumps ending in hand and led the Q, covered by West and won in dummy.
The last trump was drawn. West's J and a spade were conceded. In total the defence won 3 spades, 1 heart and 1 diamond.

West would have done even better by ducking the Q lead. A 2nd diamond would be ruffed by East and West would later still win a diamond and a spade.
How was West to know that East had a fourth trump heart to ruff with?

Trump Suit Preference Count
If playing "Trump Suit Preference Count", East's first shows preference for clubs, having nothing in diamonds.
With hearts trump, and spades already discouraged at trick one, clubs and diamonds remained. Clubs is the lower ranking of those two suits.
By first playing the lowest of 8765, the 5, East encourages the lower of clubs rather than a diamond, suit preference.

In next following to trump plays, East "gives count" in the 'lowest suit of unknown count'. East's clubs number 5, odd. "Odd is signalled low" and "even is signalled high".
Of the remaining 876, lowest is the 6, played to show an odd number.
How does East signal when following to West spade leads?
To partner West's K lead, East with neither Q nor J discourages with the lowest spade held, the 7 (from 987).
To the next spade play, with two spades remaining, East plays the 9 (from 98).
High-low shows an even number of remaining cards in the suit (remainder count).
To the 3rd spade lead, East plays the last spade, the 8, confirming that the 9 was higher.
To West, East signalled odds spades AND 12 spades had been played and West had the last one still in hand.

When West sees South win the Q, West should wonder of the first round T finesse from QT9x opposite AKxx.
Simple. South didn't have 4 hearts. South wouldn't have finesssed the T. South had only 3 hearts. East had 4 hearts.
East then started with 3 spades, 4 hearts and an odd number of clubs.

If East's diamonds and clubs number (13total-3spades-4hearts=) 6, then East clubs number 5 or 3 or 1.
If East held 1 club, then South would be holding, of the eight clubs that West does not see combined with dummy the remaining, exactly 7.
South bid 1 on a 3 card suit holding 7 clubs??? With 5 clubs still bid a 3 card heart suit with only 4 points? Nah. Must have only 3 clubs then.
With proper and dependable signalling and use of deductive reasoning, West should find East to have 3 spades, 4 hearts, 1 diamond and 5 clubs.
South then would have, by subtraction, 3 spades, 3 hearts, 4 diamonds and 3 clubs for more than one reason.

Getting to 3N or Avoiding 4
Either South must bid a 3 card suit at the higher 2 level, clubs, or North must be prepared for a 3 card heart suit in order for the pair to get to the "choice" 3N contract.
There are a number of ways to reach 3N:

NORTH  A54  AK32  A832  AK  KQJ6  J4  KJ54  QJ5    987  8765  6  T9876    T32  QT9  QT97  432

Dealer: West    Vul: None   MP Scoring West 1 1 Pass Pass North X 2 23 Pass East Pass Pass Pass Pass South 11 22 3N4

1 3+ hearts, 0 to 8 points
2 3+ hearts, 0 to 5 points
3 Invitation to game of 3 to 5 points
4 Diamond stopper with fewer than 5 hearts and between 3 and 5 points