{HEAD ~ A side ridge line} 13 of {TAIL ~ the blade portion} 12b forms a cutting edge 
of
{ HEAD ~ A side ridge line } 13 of { TAIL ~ the blade portion } 12b forms a cutting edge
HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH