Patent ID: 8422345

Claim:
A reproduction method for reproducing a rewritable and readable optical information storage medium (i) which includes n (n is an integer of not less than 2) pieces of information recording layers each including a recording mark having a length shorter than an optical system resolution limit, the recording mark being formed based on a 1-7PP modulation method, and (ii) which includes an area located near a center hole of the rewritable and readable optical information storage medium in which area medium information on a structure of the rewritable and readable optical information storage medium is stored, said reproduction method comprising: setting reproduction laser power to satisfy Pr 1 <Pm and Pr 1 of not less than 1.0 mW but less than 1.1 mW, where Pr 1 is reproduction laser power for reading a first information recording layer, in the rewritable and readable optical information storage medium, that is closest to a reproduction-laser-incident surface of the rewritable and readable optical information storage medium, and Prn is reproduction laser power for reading an nth information recording layer, in the rewritable and readable optical information storage medium, that is farthest from the reproduction-laser-incident surface; and reading recorded information from the rewritable and readable optical information storage medium by use of a reproduction clock determined based on the medium information.