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# Oteai

The Oteai (大手合) was a tournament used by Nihon Ki-in and Kansai Ki-in
in 1927-2003 (resp. 2004) to determine the dan rank of their members.
Players were 1-dan to 8-dan professionals who could earn a promotion
by getting a large enough point average in a series of consecutive
Oteai games.
Games were played without komi, but a win with White
gave more points than a win with Black, and a win against
a strong opponent gave more points than a win against a weak opponent.

## Games

At the moment, only some games from
1934,
1967,
1968,
1969,
1970,
1972,
1974,
and 1976 are available.

## Points

The details have varied over time. Around 1970 the Nihon Ki-in rules
were as follows:

Each year, 1-3 dans play (at most) 12 times, 4-dans 10 times, 5-8 dans 8 times
(and 9-dans do not participate since they cannot be promoted any further).

The players are divided in two groups: 1-4 dans and 5-8 dans,
so that the rank difference in a group is at most 3.
A player of rank r earns points as follows:

opponent rank | color |
win | jigo | loss |

r | B | 75 | 45 | 15 |

r | W | 105 | 75 | 45 |

r+1 | B | 80 | 50 | 20 |

r+1 | W | 110 | 80 | 50 |

r−1 | B | 70 | 40 | 10 |

r−1 | W | 100 | 70 | 40 |

r+2 | B | 90 | 60 | 30 |

r−2 | W | 90 | 60 | 30 |

r+3 | B | 100 | 70 | 40 |

r−3 | W | 80 | 50 | 20 |

When the random draw of opponent pairs selects a pair of players,
they play each other in three successive years. Such a series of
three games is aborted if one of the players is promoted.
The handicap depends on the rank difference.

rank difference | handicap | color |

0 | *tagaisen* |
players alternate in color |

1 | *sen-ai-sen* |
the weaker player has Black twice and White once |

2 | *sen* |
the weaker player always has Black |

3 | *senban* |
the weaker player always has Black |

In earlier times the handicap for a rank difference 3 was
*sen-ni-sen*: the weaker player got a 2-stone handicap
one out of three games. The above table was extended by two lines
for the case a 2-stone handicap was received or given.

opponent rank | color |
win | jigo | loss |

r+3 | B | 70 | 40 | 10 |

r−3 | W | 110 | 80 | 50 |

As can be seen from the above tables, each game has a total value
of 120 points, shared between winner and loser. If a player has
a sufficiently high point average over a sufficiently long series
of games, he can claim promotion. The player can choose the start
and length of the series.

minimum game series length |

| point average |

rank | 75 | 70 | 67.5 |

1-dan | 8 | 12 | 16 |

2-dan | 10 | 14 | 18 |

3-dan | 12 | 16 | 20 |

4-dan | 14 | 18 | 22 |

5-dan | 16 | 20 | 24 |

6-dan | 18 | 22 | 26 |

7-dan | 20 | 24 | 28 |

8-dan | 22 | 26 | 30 |

### Comments for 1968

Looking at the 1968 games, we note several games between
low-dans and high-dans.
Also, a game between Nabeshima Ichiro (7p) and Kano Yoshinori (9p)
shortly after the latter was promoted to 9-dan.
The rank difference is at most 2, except in the games between
Fukui Susumu (3p) and Kobayashi Reiko (6p), and between
Tsuchida Masamitsu (5p) and Ishii Kunio (8p), but both
Kobayashi Reiko and Ishii Kunio were promoted earlier in 1968,
so probably these games had been scheduled before the promotion.