There are still unclear points regarding this picture. "枝" is probably a concept close to a vector. However, it is puzzling that the angle between the "北-北" axis and the "南-南" axis is 30 degrees.
BAIEN may not have felt the need to reflect the inclination accurately of the earth's axis. Because all his maps or diagrams are patterned, and even the most realistic is not a realistic depiction.
This picture combines the annual and diurnal motion into one. Paper and ink were valuable items in the Edo period, so BAIEN compressed all expressions. For the reason, "GENGO" has become a very esoteric book.
What is characteristic in this figure is that both ends of the earth axis are "北"-north-, which means BAIEN has set the earth axis as the "north axis".
Similarly, BAIEN provides both ends of the axis perpendicular to the ecliptic plane as "南"-south-, so it is named "south axis". And the celestial equator is "西"-west- and the equator is "東"-east-. The two words mean "the way to the west" and "the way to the east".
Of course, that is the direction seen from the global ecosystem. That indicates that BAIEN has expanded the east, west, south, and north directions, which indicate plane directions, to a celestial scale concept.
This idea was not from the teachings of a monk Ninmon of Tendai. That was from the ancient Greek Astronomy, which the Jesuit Mateo Rich brought to the Ming Dynasty.
The philosopher of ancient Greece had thought the shape of the universe consisted of layers of spheres. But Chinese had thought the world was a four-sided figure seeming infinitely vast under the large canopy. The religion of the Ming Dynasty had been Mingjiao which had been Chinese Manichaeism transformed into Buddhism.
Because of Manichaeism based on dualism, the Chinese thinkers of that age had been able to accept the different world view. The Chinese astronomer of Ming Dynasty didn't exclude the utterly different world view from the traditional world shape of China.
The world view of ancient Greek that for orthodox for the Catholic Society. That changed the nature's shape of the Chinese scholar who had thought the earth was a square, and produced some historically essential works. The most critical work among them is "Tenkei wakumon".
This fact means that the astronomical views of ancient Greece and BAIEN closely linked beyond the 2000 historical gap. That was the history of the world behind Europian history that even great historians like Arnold Toinbee did not know, that is, the history of China and japan from when the early modern times to the modern times.
There is certainly a historical fact that the early modern Japanese folk thinker's thoughts erected through the Christian mission from ancient Greece to Mateo Rich in China. In the process, great thinkers and astronomers represented by MIURA BAIEN and Asada Goryu and many other thinkers were born.
Many folk scholars in the Edo era read this book, not just BAIEN, and Goryu, etc. As a result, Japanese astronomy in the middle of the Edo period had made dramatic progress.
The transformation of world view brought to China by Mateo Rich was not the problem about the center of immovability in the universe, but what about the shape of the universe. Until he taught to Chinese people about ancient Greek astronomy, both Chinese and Japanese thought the earth was a square.
Asada Goryu, who has remained as the name "Crater Asada" in the moon, was a lifetime friend of BAIEN and gained much of his astronomical knowledge from the book "Tenkei Wakumon". BAIEN also gained a lot of knowledge from the book and Yoshio Kosaku, a Dutch interpreter in Nagasaki. Motoori Norinaga also studied astronomy in his twenties, and that was the driving force for his subsequent research. Many such thinkers had been born in the middle of Edo period.
The idea that the earth is a sphere and has been floating in the space brought about a revolution in the outlook on nature in the Ming Dynasty Chinese thinkers and the revolutionary influence on Japanese thinkers and became one of the driving forces of the Meiji Restoration. But the idea did not spread in China because the country was too big.
The picture below may be useful as a reference. Assuming BAIEN was able to use PC, he would have drawn his figures in 3D.