Theory of the introduction of Shogi via Southeast Asia: Viewed from the forms of Makruk pieces—Study of the reversing of promoted Bia pieces

In the late 19th century, the similarity between Thai Makruk and Japanese Shogi was pointed out for the first time (Falkener 1892). Subsequently, there was a negative view that the similarity was just coincidental, while in 1971, Alex Randolph again focused on the similarity between Makruk and Japanese Shogi, and wrote that Shogi was introduced to Japan via Southeast Asia (Randolph 1971). Different from past theories, Randolph’s work was published in Japan and gave rise to followers of Randolph in Japan who thought that the introduction of Japanese Shogi had some relation to Shogilike games in Southeast Asia (Masukawa 1977; Ouchi 1986). Concerning the introduction of Shogi to Japan, it had been vaguely thought that the game would have been introduced from China or the Korean Peninsula. However, as the similarity between Shogi-like games in Southeast Asia and Japanese Shogi was pointed out, a new research perspective was added whereby the long-distance Marine Silk Road trade might have some connection with the introduction of Shogi to Japan. Initially, Randolph and his followers assumed the existence of ports of call between Southeast Asia and Japan, while they apparently supposed that Shogi-like games in Southeast Asia had a direct influence on the establishment of Japanese Shogi. Because the current Xiangqi in China is very different from the present Japanese Shogi, they considered that Shogi-like games in Southeast Asia had not become widespread in the Chinese continent. However, there are only a few products of culture related to Southeast Asia in ancient times, and there are no records showing that ships from Southeast Asia stopped at ports of call in China before coming to the Japanese archipelago. Due to the lack of evidence, the theory that Japanese Shogi was introduced from Southeast Asia has changed as time has passed. As