Underwater ice hockey matches are played upside-down below the frozen surface wearing full scuba gear.
In the classic version of the extreme game competitors do not use any breathing apparatus, but instead go to the surface for air every 30 seconds or so.
Instead of goals, two triangular holes were carved on the top of the ice and set 15 metres apart, with the teams trying to score using a floating wooden puck. Played out by teams of two or three people, matches continued simply until the first goal.
Roman Vytovtov, head of the Nayada diving club, told the Siberian times: 'Initially, there is a slight disorientation, but we get used to very quickly. We really liked this game and we plan to gather teams from different regions of Siberia and host a full tournament next year.'