ボルト フランジ- Bolt Flange
 
Flange bolt with a flat head, M5 or M6:
The reference number is 01547-ZZXXY.
ZZ is the thread size, 05 or 06
XX is the length under the head in millimeter
Y is the plating, A for white zinc, 3 or B for black, 7 for chrome
 
This family of bolts is commonly used for crankcases from around 1985 to this day.
 
You will receive each bolt in a separate sealed plastic bag. OEM stuff is always a safe choice for quality.