A peninsula where is Dalian city (Liaoning) in the north of China and an Island in front of gulf of Shangai are very similar to the large  island shown in the top left of the map.

Another existing hypothesis is that it represents Japan.

Pictures from map and satellite, local wildlife and Tara the mother of Tibetan people with Pha Trelgen Changchup Sempa the mythical monkey-ancestor of the Tibetan people.

Probably the most precise map of Taiwan of  XVI , XVII  and XVIII centuries

Who is Tara?

An old map of east of Asia by Ortelius

Map of Piri Reis

The mystery of "Cipango" island

Tara is the Holy mother of tibetan people.

A very popular Tibetan creation myth holds that in the beginning the world was covered by water, which evaporated little by little, leaving room for animal life. To the flooded land of Tibet came a monkey that had withdrawn there to immerse himself in meditation and to follow a life of asceticism and chastity. He settled on Mount Gongori. One day, while he sat in meditation, a female demon came to seduce him. Tradition has it that she was the manifestation of the bodhisattva Tara (Jetsun Dolma in Tibetan), a symbol of compassion and protector of merchants and travelers. She threatened that if he refused to sleep with her she would visit a demon and conceive a multitude of small monsters that would destroy all living creatures. The wise monkey yielded and requested Avalokiteśvara's authorization to marry her. Avalokiteśvara blessed the monkey and the female demon, and a few months later six small monkeys were born of their union. The monkey let his six children grow up in the forest, but three years later he discovered that they had become five hundred. The fruits of the forest were no longer sufficient to feed them, and the five hundred monkeys beseeched their father to help them find food. Not knowing what to do, he went again to ask help from the god of compassion. Then Avalokiteśvara went on the mount Meru, or Sumeru (believed to correspond to today's Mount Kailash), a sacred place for Buddhists, Hindus, Jains and Bönpo. Some say that at the top of the mountain he gathered a handful of barley, others that he extracted five cereals from his own body to offer to the monkey father. Then the monkey father learned agriculture and, after a good harvest, could finally feed all his children. As they fed on the cereals, the monkeys gradually lost their hair and their tails. They also started to use bone and stone implements, then made clothes and built houses, forming a civilization from which the Tibetan people descended.

https://en.wikipedia.org/wiki/Pha_Trelgen_Changchup_Sempa