The tenure of most major league managers comes to an end when they are fired. More recently, for example, the transactions column included notice the Washington Nationals fired manager Matt Williams and the Seattle Mariners dismissed manager Lloyd McClendon.
Somehow, though, Japanese managers don't get "fired" any more. They either "step down," "resign," "leave the team" or take a "rest" from which they never return.
Orix Buffaloes skipper Hiroshi Moriwaki officially took a kyuyo (leave of absence) in May and did not come back. First-year Rakuten Eagles field boss Hiromoto "Dave" Okubo announced in September he would step aside at season's end to take responsibility for the team's last-place standing in 2015.