VI.    EXTRAS

The first three trump spots played from a longer trump holding constitute a prism signal. Partner considers the signal and the total number of signaler's trumps to learn the identity of declarer's single suit.

The warm-up grand in the "Extra Trump" category features   an Odd Prism and five trumps with East:

West leads a trump against seven spades. Declarer, who started with six solid, wins and continues spades. East follows to five rounds:  6-5-4-8-9. Next, the heart ace, heart king, and a heart ruffed with declarer's last trump. East's first three trump spots 6_5...4 promise an even single suit (not spades- odd.) East's prism signal reads I am even in clubs.

West to discard in this position as declarer leads the heart ten from dummy and trumps in the closed hand:

Even clubs Odd Prism Odd clubs

West decides that declarer holds three clubs. (Partner with four clubs and one diamond would have advanced the 3NT preempt.) Declarer's hand pattern index is three: 6-3-2-2. The applicable distribution is 6=2=2=3. Therefore, West unguards the diamond queen, and holds clubs.

The full deal:

Switch the minor suit deuces in the diagram on the left. East signals: 6_4...5. I am even in diamonds.

West unguards clubs and saves diamonds.

The full deal:

This deal features a Minor Prism and four trumps with East:

West leads the diamond king and avoids a black suit squeeze for the moment by shifting to a low club. (If West continues diamonds...) Declarer guesses correctly, playing dummy's king. Four rounds of trump are   played- East follows 5-7-6-8. Declarer discards a spade and a club from dummy.

Declarer plays a fifth trump, discarding a diamond; East and West also shed diamonds. West is put on lead with a diamond to the ace, and must ensure two tricks in this position:

East with even trumps signals 5_7...6  promising an odd single suit...diamonds.

To rectify the count for the black suit squeeze, declarer must present the defense with a third trick. Thus, a low club exit to East's queen aids declarer's effort and is bad for the defense.

A low spade exit neither rectifies the count nor costs a trick. Declarer, 2=6=2=3 with king-small in spades, cannot untangle the spade suit for a third trick. Declarer wins the spade and plays a club to East's queen to rectify the count, but then a spade from East sabotages declarer's communications. The spade eight is West's only effective continuation in the above position.

South and East trade black fours. Replay the hand - diamond ace, club king, five top trumps (hearts), and a diamond exit to West- East following with his four (even) trumps 6-5-7-8.

	Even hearts Minor Prism Odd spades
	Index three 6-3-2-2 pattern 3=6=2=2 distribution

A spade exit concedes the game-going trick. Instead, West can cash the club ace and exit with a club to defeat the contract.

The full deal:

Three trumps are necessary to encode a prism signal. To hold more trumps is a luxury; to hold fewer, unfortunately, the norm.