When I search for "6301" though I see three results:
JIS A 6301: Sound absorbing materials
JIS D 6301: Standard for construction and performance of truck cranes, wheel cranes and crawler cranes
JIS X 6301: Identification cards -- Physical characteristics
This website has all four parts of JIS-K-6301 for sale. $785 per section though! I have no idea what a "normal" price is for JIS standard, though, having only purchased ANSI stuff for ~$100.