1. Specially designed HELMETS with integrated face shields are worn for protection, but minor injuries like black eyes still occur.

2. For each set, a machine prepares 90 SNOWBALLS that must measure between 2.56 and 2.76 inches in diameter.

3. Some skilled teams concentrate their volleys on a single player; others prefer a deadly combo of lobs and fastballs. Less serious teams often eschew STRATEGY and instead engage in what is known as baka nage ("stupid chucking").

4. The most serious teams are sponsored by the likes of Sapporo beer and Japan Airlines. They analyze video of other teams, and in the off-season PRACTICE indoors, using polyethylene balls and fighting from behind wooden walls.

5. THE FIELD is as wide as a tennis court and twice as long. Each side has four three-foot snow walls for players to hide behind and throw from. Team flags are planted 33 feet from the ends of the field.

6. Two seven-member TEAMS compete in three-minute sets. Get hit and you're out. A team wins either by having the most players standing at the end of the set or by snatching the other team's flag without getting pasted. A team must win two sets to advance.