[1] However, the blocking cards provide the necessary communication between hands after the squeeze has been effected.
Unblocking in the correct order allows the squeezing player to cash the newly created winner; but this requires an exact count of the hand – or a correct guess.
One of those aces will serve as entry or re-entry to whichever queen is established by the squeeze.
When South cashes the ♣A as squeeze card, West must blank (unguard) one of his kings.
If the complete hand is as shown here, then East is squeezed; but if declarer cannot be certain from the previous bidding and play who holds both kings, he will have to guess which suit to play first if the defenders discard in different suits (as they should).