Why are Japanese bureaucrats said to be so competent?

In comparison with ministers, who change their job every time the prime minister changes, bureaucrats normally work for one ministry or agency on a lifetime employment basis, which means they have enough time to develop their expertise in certain areas.
To work as a bureaucrat in one of the central ministries or agencies, one must pass the State Higher Civil Service Examinations.
The fact that the majority of those who pass the examinations are graduates of well-known universities contributes to the reputation bureaucrats have of being very capable individuals.
The problem is that some officials are so dedicated to their duties that they fall into the pit of being territorial about their jobs.
This results in what is called "vertically-split administration," which inhibits close-knit relations between the various ministries and agencies.
With this type of red tape, it is common that something that could just as well be decided at a single office is sent around from one office or ministry to another to get a series of stamps of approval, even if it should not really be necessary to do so.
It is Japan's task for the future to implement administrative reform while encouraging efficiency and flexibility.