Originally broadcast on Fuji TV in Japan, Viking can be seen around Europe on Eurosport2 at different times of the week. The English edited version is commentated on by Colin Bryce.
There are four stages, all themed like a Viking ship, that contestants must get through to be victorious and get crowned the Ultimate Viking.
Stage one is the Marine Stage, stage two is the Adventure Stage, and third is the Fantasy Stage. If a contestant falls in the water, or disqualifies themselves in any other way, on any part of a course they are eliminated.
Any contestant who manages to get through these three stages, each getting progressively harder, is faced with stage four - the Final Viking. Only one person has ever reached this final stage but they were unsuccessful in completing it in time.
The obstacles in the first three stages are occasionally changed and swapped around.
There are several different versions of Viking. The first is where single contestants all compete against each other to be crowned the Ultimate Viking, as explained above. The second version is Family Viking, and the other is Celebrity Viking.
In Family Viking the contestants play in pairs with another family member. The most common pairing is a parent and their child, or a husband and wife.
Working as a team they must get through the Marine, Adventure and Fantasy stages. Again if anyone messes up on any part of a course they are knocked out of the competition.
In regular Viking, if contestants don't complete a course within the set time limit then they are also knocked out, but in family Viking, if not enough pairs complete the first stage, the teams who managed to get the furthest are let through to stage two.
Stage four is different in the family version. Instead of it being in Tokyo Bay with the other stages, it's in the sea just off the shore of Okinawa Beach. The first family to complete this final stage wins a brand new Honda car.
This is pretty much the same as the other versions, except parts are a race. Two celebrities play at the same time. The ones with the fastest times move on to the next stage.