The Daymio Takeda Shingen (1521 - 1573) from the Minamoto family promoted the mounted archers (Kisha) and tried to use the Chinese strategy to do so. Shibata Kanjuro XX, Sendai has repeatedly pointed out the meaning of these four terms.

 

Fu   as swift as the wind The release of the arrow - Hanare - should be as fast as the wind
Rin   silent as the woods  Kyudo is a silent practice that requires inner and outer peace.
Ka  

destructive like the fire (thinking)

Fire destroys and makes room for new things. For Kyudo this means to free our thinking and practice with an open mind.

Zan   Immobile like a mountain  The stand - Dozukuri - should be like a mountain - immovable and unshakable.

 

 Kalligrafie von Shibata Kanjuro XX, Sendai