#4 - KM#73a, Japanese 10 yen, possibly dated Showa 48 (1973) but picture is too fuzzy for me to be sure; bronze, worth face value of <13 cents. #6 - KM#6a, South Korean 10 Won, brass, also worth face value of <1 cent.
#6 is a 10 won Korean coin (about 1¢). The words at the bottom "Hang Kook Oon Hang" means "Korean Bank"...(I think). I was in Korea in 1991 and the lowest denomination coin in general circulation was the 100 won coins (about 12.5¢). Funny thing about the Korean 100 won coin...it has the exact same size and weight as the US quarter. In other words, they work fine in US vending machines, but cost half as much!
I lived in the area for a few year in the '80s & '90s...but I didn't collect coins then so I could be wrong.
Read post #3 in this thread. The picture is clearer than the original, and the date is actually Showa 49 (1974), not 48 as I originally guessed.