Based on the premise of plain strain thinned crust for the first order approximation

the paleo tectonics of northwest Pacific margin at the beginning of collision between Indian and Eurasian Plates have been reconstructed in this paper.The suture between the two plates was located at 26° southward

the north coast of South China Sea at about 14° southward

the north coast of Japan sea at about 4.5° south and Southwest Japan Island at about 8.5° south to the their present positions respectivily.The collision of Indian Plate and Eurasian Plate accelerated the north retreat of Eurasian Plate

caused right shear along the margin from Sumatera to Far East of Russia and the opening of marginal basins including South Chian Sea

Sulu Sea

Celebes Sea

Philippine Sea

Japan Sea

Okhotsk Sea and so on.These basins constituted a huge chain dextral pull-apart rift system in order to be balanced kinematically

Qinling and Bajkalj Stanovoj was the derived sinistral R′fault belt.Globally

the north retreat of Eurasia Plate possibly harmonized with south shift of North American Plate

and in the east margin of Pacific Plate

San Andreas Fault took dextral displacement.