A signal having {TAIL ~ a predetermined pattern} is written in a predetermined region of an optical disc at a plurality of {HEAD ~ different write power levels} Pwm 
A signal having { TAIL ~ a predetermined pattern } is written in a predetermined region of an optical disc at a plurality of { HEAD ~ different write power levels } Pwm
OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH