At the expiration of this period, when between the ages of twenty to twenty-three, the midshipmen enter for a technical pass-examination for sho-i (second-class sub-lieutenant). If he fails (as a proportion do) he is put back six months. He then has a second try. If he fails in this attempt his services are dispensed with for good and all.
Passed midshipmen become sub-lieutenants, not by virtue of the examination only, but in order of seniority obtained in the examination, and as vacancies occur.
As sub-lieutenants they leave examinations behind them, but they have to write essays on naval subjects. According to how the sho-i does in these, he passes up through into the higher class of sub-lieutenants. The best take about one year to become a tchu-i (first-class sub-lieutenant), the worst take much longer.
After two years’ service as first-class sub-lieutenant a tchu-i is eligible for promotion to taï-i (lieutenant).
Promotion is entirely by selection in this and all senior ranks. The very youngest age at which an officer can become a taï-i is twenty-three. Twenty-four to twenty-five is nearer the average. A non-promoted tchu-i is compulsorily retired at the age of forty-two; but there are none so old as that.
After eight years’ service a taï-i is eligible for promotion (by selection entirely) to lieutenant-commander. Thirty-one is the youngest age for this. Lieutenant-commander is a distinct rank, intermediate between lieutenant and commander. Its holder is entitled to the courtesy rank of “captain,” and officially so addressed. In command of a small ship he is a scho-sa; serving in a big ship he is a hojutsho (gunnery lieutenant), suirisho (torpedo lieutenant) or a kokisho (navigator).
A lieutenant-commander is selected for tchu-sa (commander) without any definite service time.
Thence, still entirely by selection he can pass on upwards through the usual higher grades of captain, rear-admiral, and vice-admiral (kan-cho, scho-sho, and tucho). The average age at which an officer becomes a scho-cho (rear-admiral) is forty-five. The retiring age is sixty-five, but comparatively few live so long.
To be selected for taï-sho (admiral), a tucho must have been in command of a fleet two years, and, further, have been so in actual war.
A higher nominal rank still exists of admiral of the fleet—destined for a full admiral who has had meritorious war service in that rank; but there are none at present.