The characteristic of the Yōryū Fourth File Rook is that it keeps the position of the king at 38 (72 for White).
While moving the king to a place other than 38 to develop the castle is also possible, that is different from the original conception of the Yōryū Fourth File Rook.
The idea of castling the king in the Cozy castle in normal Fourth File Rook openings has existed since the early days of classical shogi, and has also been used in conventional modern shogi, as attested by numerous examples, and thus, it cannot be said that Ōhashi's Yōryū Fourth File Rook is the first strategy in using it.
[2] Compared to a Mino castle, the 72-King position has some advantages, such as avoiding the bishop's diagonal and being strong against counters when doing edge attacks.
In Yōryū Fourth File Rook, the player takes advantage of the above points to develop the formation as occasion may demand.