ON occasions of celebration or when a group is seing someone off (e.g When a couple is going off on honeymoon or a company employy is leaving to take up new pos), it is the costume in japan to raise both arms above the head three times, shouting " BANZAI" each time, this costume started in Meiji Era as the Japanese version of the western " three cheers", and become very popular with the rise ofnasionalism from the end of the nineteeth ceentury onwards at parties or reseptions, one of the more important people present ussually take the lead, saying "So and So company BANZAI" or "MR so and So BANZAI" : everyone then perform the Banzai cheer in unison.
The "Hip, hip Horay" of the Western three cheers is still widely used by Cheerleaders at sport matches, in the form (for example " Furee, Furee Waseda" (Hooray, hooray for Waseda)
source
BOOK : GATES TO JAPAN (Its People and Society)
by: Gen Itasaka