Does the writing on the head of japanese bolts eg the single number. Define its tensile strength?
Yep - got it in one :yes
should go from 8.8 to 10.9 to 12.9 low to highest, google bolt gradings and some reference table should pop up.
if you using imperial bolts 3 lines is grade 5 and 5 lines is grade 8
correct me if im wrong