What is the historical backbone of writing system throughout eastern asia

China is the historical backbone of writing system throughout eastern Asia.
China is responsible for all writing systems in these parts of Asia - many countries around China, including Japan are still using the writing system that China developed centuries ago. The Chinese were even the first people ever to use paper for writing - before that, many other materials were used for that.

They immigrated for religious freedom

Geothermic gradient is the rate of increasing temperature with respect to increasing the depth in the earths interior. away from tech tonic plates boundaries, it is about 25-40 c/km (72-87 degrees f/mi) of depth near the surface in most of the world.