The men’s hockey tournament in Sochi, Russia, which begins Wednesday, will feature more than 140 N.H.L. players. But Olympic hockey, governed by the International Ice Hockey Federation, is not quite the same as N.H.L. hockey. Here are some of the differences:

WIDTH OF ICE The Vancouver Olympic hockey tournament, won by Canada, was played on N.H.L.-size ice. But in Sochi, the rink returns to international standards. While N.H.L. and Olympic rinks are both about 200 feet long, Olympic ice is roughly 100 feet wide, about 15 feet wider than in the N.H.L.

Those 15 additional feet present challenges for defensemen inexperienced on the larger sheet. It gives attacking forwards more time and space to maneuver on the outside, so defenders cannot always check attackers by forcing them to the boards as they might in North America. Goalies also will rarely have to worry about a shot from the distant sideboards.

The bigger ice had much to do with roster selection for the United States and Canada. For Team USA, forward Bobby Ryan’s skating -- not as strong as Blake Wheeler’s -- factored into his exclusion.

Canada Coach Mike Babcock emphasized the need to have right- and left-handed shooting defensemen play their natural side on the big ice, resulting in Brent Seabrook being left behind.