The All Japan Middle School Mahjong Tournament is an annual event in which Middle Schools all over Japan participate. Unlike the High School tournament, there is a City Tournament before the Prefectural Tournament, all of which leads towards the Inter Middle School Championships (commonly called the "Inter Middle"). Comparatively to the the Inter High, the Inter Middle is much smaller.
The entire tournament is split into a boys' tournament and a girls' tournament. Saki almost exclusively depicts the girl's tournament.
The Inter Middle contains two tournaments: the team tournament and the individual tournament. In the team tournament, schools participate with a 5-person team and additional reserve members. In the individual tournament, any student may participate.
The team tournament consists of 4-team free-for-all matches and uses best-of-five system, in which schools aim to win 3 out of 5 of the hanchan. In the event no school has won 3 hanchan, the school with the highest point total is declared the winner and moves onto the next round. Each player starts with 30,000 points, and points reset after players switch. No bonuses for placings in individual hanchans are calculated.
The positions of the 5 players on the team are called the following:
- Vanguard (先鋒 senpo, "first spearhead"). The modern position for the ace player.
- Sergeant (次鋒 jihou, "second spearhead").
- Lieutenant/Centerfield (中堅 chuuken, "main body"). Traditional ace position.
- Vice-captain (副将 fukushou, "second in command")
- Captain (大将 taishou, "general"). Not to be confused with the English word "Captain" used describe the leader of the team.
The starting players as well as the substitutes are registered before the tournament. The rules allow limited substitutions of players. From the registered starting order, it is allowed to switch one position after each match. Also, a reserve member may play instead of a starting member, but this is limited to a substitution in a game each day.
Note that players from different schools can play practice matches against each other even if they are competing in the same tournament which is not allowed in the Inter High.