Tachi is 2 feet (about 60cm) with hanging its edge down from hip by Samurai.
It needed to be made considerable
length and curve, when fighting
style was mainly cavalry battle
on the end of Heian period through
the beginning of Muromachi period.
It exhibits by turning an edge
down.
Katana
Katana is 2 feet (about 60cm).
The edge was turned up and was
very used for the waist.
It needed to be made shorter
and flatter than Tachi as a
result of a shift from cavalry
to infantry action on Muromachi
period through the end of Edo
period.
It exhibits by turning an edge
up.
Wakizashi
Wakizashi is no fewer than 1 foot, nor more than 2 feet length used for
the waist like the sword. Less than 40cm in a short sword is called Kowakizashi.
Tanto
Tanto is less than 1 foot,
and called Koshigatana or Aikuchi.
