5'10" is tall for a Japanese guy?

The average height for an American male is 5'9, so 5'10 is tall by any standard.

Our Sun dwarfs the Earth, Arcturus dwarfs our Sun, Betelgeuse dwarfs Arcturus....

My point is, you're a fuckin simpleton. I take shits that are smarter than you.

The man is 90 years old now. He was in his 20s & 30s in the 1940s & 1950s.

The average Japanese man is 5ft7.5 today. (All adult males)
The average American man is 5ft9 today. (All adult males)

Back in WWII I know the average young American man being conscripted was around 5ft8. Assuming the height difference between the Japanese and Americans was similar back then that would make the average young Japanese man back in the early 1950s around 5ft6.5. So he would have been 3.5 inches taller than average back then.

That's comparable to a 6ft0.5 man in America today. (I have to note this is an 6ft0.5 accurately measured man. You need to understand many men who are 5ft10 or 5ft11 will claim to be 6ft. An actual 6ft person is a touch taller than many people realize).

When judging height you need to factor in numerous aspects of the demographics such as the time period, age group, gender and nationality. People were a tad bit shorter back seven decades ago and the Japanese in general are a tad bit shorter than Americans. Factoring both these together you will realize calling a 5ft10 Japanese man tall in the 1950s isn't that strange.

Ex. Many people would call someone like Henry Cavill (6ft1) tall. He's only half an inch taller versus American men than Tatsuya was for Japanese men back in his youth.