Sclerochronology, the study of periodic increments in skeletal organisms, can decipher the life history and environmental records preserved in fossil shells. In this study, we introduced the term of Sclerochronology and study methods, reviewed the history and development of this science. Living and buried oyster shells from Bohai Bay were selected for case study, micro-growth patterns and consecutive micro-sample along a profile perpendicular to skeletal growth increments were analyzed for shell growth age estimation. Our work takes the morphological features on ligamental surface, together with the corresponding translucent growth bands on the shell cross-section into account with stable isotope profiles, to determine if concave bottoms and growth breaks on convex band on the shell resilifer surface, and their corresponding translucent growth bands on shell cross-sections, were formed seasonally in the oyster shells of Crassostrea gigas. Further, we aim to derive ontogenetic information from the oyster shells of C. gigas. Results show that concave bottoms on resilifer surface, which were formed during lowest temperature recorded by shell in winter seasons, and corresponding translucent growth lines on cross-section of left valve, are suitable indicators of annual growth increments in these Pacific oyster shells of west Bohai Bay. Beside these concave bottoms and corresponding translucent growth lines, growth breaks near convex tops on resilifer surface and corresponding translucent growth lines on cross-sections, which were results of spawning during spring season, are also suitable indicators of annual growth increments. The spawning growth breaks and alternated concave bottoms are pair of excellent indicators for annual growth increment. The life spans, growth rates, and the timing of spawning and death can be determined from the ligament increments of these oyster shells.