I’m not sure how the other companies work but at the very least, among the companies I’ve been a part of, including part-time work during my schooling days, Japan’s half-day leave makes more sense.
When I was working in Singapore, morning half literally referred to the period before noon. If I were to work from 930 to 630 daily, a half-day leave in the morning would mean i had to report to work at 1pm (given that 12 to 1 is lunch hour). With the afternoon half being from 1 to 630, one is practically off work from lunch hour which begins at 12.
If you think about it, wouldn’t most people rather take the afternoon half off since it’s a full 6.5 hours compared with the morning which is only 3.5 hour?
At my current company, people who take the morning half off work report to work at 230 while those who take the afternoon half leave the office at 230. Regardless which half you take, you work 4 hours and rest 4 hours. And you thought Singaporeans are clever.
Then again, we probably are, since most of us never took the morning half off.