We've tried to update and clear out the very complex history of shogi and its large variants in a Word of Chess (McFarland, 2017). We were (strongly) helped by Erwann Le Pelleter, speaker of Japanese, who had access to several historical sources in this language.
Dai shogi is first mentioned in the Taiki, a diary made between 1135-1155. The first details on rules are given in the Nichureki, a text compiled in 1210-1221 but containing some parts that might be older. The Nichureki contains a description of a small shogi (that we call Heian Shogi) on 8x8 or 9x8 or 9x9, and THIS Dai Shogi on 13x13 that we call Heian Dai Shogi. The description of the moves of the pieces is short. For the Flying Dragon (Hiryu) it simply says "it flies in the four diagonal", if the translation is correct. Indeed, I agree that it is not enough to affirm that this move was the move of the modern Bishop. As HG remarks, it could also be the move of the piece with the same name at Dai Shogi (on 15x15). But it might be something different too as the indications for several other pieces, Copper General, Iron General, Side Mover, seem to describes different moves than the ones later known for Dai Shogi.
The Futsu shodoshu, a prayer anthology published around 1300 also evokes a Sho Shogi (sho=small) and a Dai Shogi, with a Flying Chariot (Hisha) for the 1st time in all shogi history. This Hisha was maybe playing like the Rook. Contrary to what many authors have said by copying each other, this text had no indication on the board size nor the total number of pieces.
The 15x15 form (we call it Dai Shogi) would have been presented in the Shogi Shushu no Zu, a book from 1443 now lost but which is known from copied passages in later historical books, the earliest being the Shogi Zu from 1591. Dai dai shogi, Maka dai dai shogi and Tai shogi were also in the Shogi Zu, and maybe, they were also known in 1443.
Chu shogi, on 12x12 is first mentioned in the mid 14th c. and appears several times in the 15th c.
We've tried to update and clear out the very complex history of shogi and its large variants in a Word of Chess (McFarland, 2017). We were (strongly) helped by Erwann Le Pelleter, speaker of Japanese, who had access to several historical sources in this language.
Dai shogi is first mentioned in the Taiki, a diary made between 1135-1155. The first details on rules are given in the Nichureki, a text compiled in 1210-1221 but containing some parts that might be older. The Nichureki contains a description of a small shogi (that we call Heian Shogi) on 8x8 or 9x8 or 9x9, and THIS Dai Shogi on 13x13 that we call Heian Dai Shogi. The description of the moves of the pieces is short. For the Flying Dragon (Hiryu) it simply says "it flies in the four diagonal", if the translation is correct. Indeed, I agree that it is not enough to affirm that this move was the move of the modern Bishop. As HG remarks, it could also be the move of the piece with the same name at Dai Shogi (on 15x15). But it might be something different too as the indications for several other pieces, Copper General, Iron General, Side Mover, seem to describes different moves than the ones later known for Dai Shogi.
The Futsu shodoshu, a prayer anthology published around 1300 also evokes a Sho Shogi (sho=small) and a Dai Shogi, with a Flying Chariot (Hisha) for the 1st time in all shogi history. This Hisha was maybe playing like the Rook. Contrary to what many authors have said by copying each other, this text had no indication on the board size nor the total number of pieces.
The 15x15 form (we call it Dai Shogi) would have been presented in the Shogi Shushu no Zu, a book from 1443 now lost but which is known from copied passages in later historical books, the earliest being the Shogi Zu from 1591. Dai dai shogi, Maka dai dai shogi and Tai shogi were also in the Shogi Zu, and maybe, they were also known in 1443.
Chu shogi, on 12x12 is first mentioned in the mid 14th c. and appears several times in the 15th c.