Source: The Spokesman-Review – 8 Sep 1943

A Q 2
A Q 10 8
Q J 10 9 8 7
K J 10 9
5 4 3 2

K Q J 9 8
8 7 6 5 4 3

6 5 4 3 2
10 7

K J 9 7 6
A K
A 6 5 4 3 2

The order of preference of plays is: Trumping, establishing suit, unblocking, strip-and-end play, squeeze, infrequent coups, finesse. One or more of these types of plays are used in the play of any deal. In the class known as unblocking plays, you must include all plays that involve entries. That is, you think of them as unblocking plays when you prepare for getting into a hand or holding the lead somewhere.

Among traditional unblocking plays is the deal you see above. It has been used in contests and as entertainment for many years in auction bridge and even in whist, I suppose.

Farfetched.

While the unblocking feature is the spectacular feat here, it gets the help of trump plays and winds up with the establishment of a suit. It is a farfetched but educational drill.

South must make seven hearts. West leads the club king. Instead of a spade, dummy must slough a diamond. South wins with the club ace and leads a trump. Dummy wins that by overtaking as low as possible. The deuce of spades is led from dummy and trumped by south. Another trump lead from south is overtaken in dummy as low as possible.

The dummy spade queen is led and triumphed by south, who lends his last trump for dummy to win. Dummy then leads the last trump, and picks up the remaining trump in west. Meantime, being now out of trumps, south sloughs the diamond ace. Dummy then leads the spade ace and south completes the un-block by sloughing the diamond king.

Dummy is still in the lead and has the now established diamonds unblocked for the remaining tricks. Had dummy sloughed a spade on the first lead, the contract could not have been made.