- Gavin, London, England
Apparently, the best Soviets were left-handed shooters, so they usually began their attacks from their left side (the opponent's right side). To shut them down, both Czech defensemen would move to their right, focusing on that half of the ice. The Czech left winger would come back to cover the spot abandoned by the left defenseman. Between the three of them, they would "lock" the entire zone.
Good story. Don't know if it's true, but to this day almost all Russians are left-handed, as are the majority of NHL players. Of course, a team can change the lock to make any forward the third man back.

