This curved Japanese sword usually measures around four to five feet or longer. Many examples are over six feet. The average (modern) 'Katana' is around 90cm long - or just under three feet. As this sword requires plenty of 'open space' to be used effectively - it could be that this is the preferable translation - which is open to debate. Being sat upon a horse grants the kind of space required and the freedom of movement needed. The speed of a charging horse would provide the power for the sword to perform its task - cutting-through the enemy - with the sword 'dragging' through the air. Even so, this Japanese sword is much longer than Western cavalry swords.
The Japanese and Chinese script used in this article is incompletely translated - which I rectify below. I have also added the proper Japanese-script name (not included in the above article). The other included historical data in acceptable for further research. I have added different photographs in this email.
The Chinese name is ' 大太刀' (Da Tai Dao) - or 'Great Grand Blade'.
The Japanese name is ' 野太刀' (No Da Chi) - or 'Field Grand Blade'. As this uses Chinese ideograms - this name can also be read as 'Ye Tai Dao' - 'Field', 'Open Space' or 'Wild' Sword - depending upon interpretive emphasis.
In Japanese script proper - this sword is named 'おおたち' or 'O-Otachi'.
The article below is auto-translated and gives a chronological record of the development of all Japanese swords - from the Tang Straight Sword to the modern Japanese Katana:
History of the Japanese Sword (English)
According to Japanese and Chinese language texts - this sword should be used only by warriors on horse-back due to its varying length (90cm-150cm or longer). This blade is designed to severe the legs of attacking enemy horses - and to cut enemy infantry soldiers across the waist area. Some Japanese Sword Schools, however, do attempt to use this sword on foot with the scabbard sometimes (but not always) secured across the back.
Shifu Adrian Chan-Wyles (b. 1967) - Lineage (Generational) Inheritor of the Ch'an Dao Hakka Gongfu System.