Haibu (haimu) refers to a ritual of bowing which includes sayusa (a series of movement from left to right to left) for expressing one's gratitude on occasions such as joi (investiture of a court rank), appointment, and shiroku (receiving a stipend) in the Imperial Court during the Heian period.
It is based on the manners of the Tang Dynasty.
While standing or sitting, one moves his or her hands to the left and right while looking both ways. This indicates that he or she doesn't know what to do with his or her hands and legs due to a feeling of great joy.
According to "Shugaisho" (an ancient encyclopedia written in the 14th century) and "Gooshikoji naifu sho," the customary bow is as follows:
After bowing twice, while standing, turn your upper body to the left stretching both your arms out to the left with sleeves together, turn right and left maintaining the same posture, then kneel down on your left knee and do the same. According to "Goshidaisho" (a commentary book written by Kanera ICHIJO on "Koke Shidai," which is a classic rule book about ceremonial and public functions), bowing twice in the beginning indicates respect for the Imperial edict, and the following dance expresses joy for receiving a favor. It is thought that the manners have changed with the times. According to "Sezoku senshin hi sho" (a ceremonial rule book written by the Emperor Gotoba), originally in the event of Chokin no Gyoko (New Year's visit to the Imperial Palace), the Emperor performed sayusa (left-right-left) and his retainers performed usayu (right-left-right), later, though, the custom changed so that the Emperor performed usayu, and the retainers performed sayusa.
When clothes were given, haibu was conducted with them on his or her shoulder (kazukemono). When a makiginu (bolt of silk) was given, haibu was conducted with it on his or her belt (koshizashi).
The haibu conducted by relatives in the event of jonin (investiture) was called Shinzokuhai.