The Nodachi/Ôdachi web files

The definition of Ôdachi 

The direct translation of "Ôdachi" is big thick sword.  Often mistaken for Nodachi which translates to field sword.  The term Nodachi is generally misused for Ôdachi.

The character for "Ô" means big or great.  The characters for "DA" and "CHI" are the same as "TACHI", the older style of sword/mounts that predate the Katana (the "CHI" is the same character as Katana and the "TÔ" in Nihontô).  

I think that to qualify as a Ôdachi the sword in question must have a blade length of 3 shaku (90.9 cm) or more, however, as with most terms in Japanese sword arts, there is no exact definition of the size of a Ôdachi.  Generally speaking, swords that are longer than normal* ones are classified as Ôdachi.

*The normal length of swords varied slightly depending on the period.  During the Edo era, the average length of a sword was about 66 - 70 cms, however during the Heian and Kamakura era it was around 80 cm.  Lengths varied during different eras because the methods of use varied also.  During the Heian and Kamakura era Samurai rode on horseback which required a longer blade (about 80 cm).  Samurai during the Edo era didn't usually ride horses, so a shorter (about 66 -70 cm) blade was more useful.

The history of Ôdachi 

It is believed that Ôdachi first appeared in the 5th Century.  This has been proven by the fact that a 117.0 cm sword from the 5th Century was unearthed from an old mound in Kumamoto. A 137.9 cm sword was unearthed from a mound in Tochigi and dated to the 5th Century.

It was believed that some such swords were used by the Gods of Japanese mythology, however, most of the swords discovered so far have only dated to the 5th Century.

For example, in Japanese mythology the sword named "Hutsunomi-tamano-tsurugi" (in Kashima Shrine, Ibaraki) was believed to have been the sword that was given to the Emperor by a God to end a revolt.  Now, research has show that the sword was made during the Heian era and is not the sword from the myth.

It seems the sword was an imitation piece, based on the sword used in mythology.  This is the reason why some swords are believed to have been used by Gods.  Another one of the reasons why people believed that the sword was used by Gods was due to the appearance of the sword.  If the sword is large and awesome, it looks like the property of a God.

The purpose of Ôdachi 

The purpose of Ôdachi can be categorized as follows:

a) As an offering to a Shrine or Gods.  Some Ôdachi were dedicated with prayer to win a war, others were placed in Shrines as legendary swords from mythology.

b) As a weapon.  From explanations in old texts, such as "Heike-monogatari, Taihei-ki" tell us that Ôdachi were used by soldiers during battles.

c) As a symbol for an army.  Some Ôdachi are too long for practical use.  They cannot be used in a battle but it is said that they could have been used as a symbol of an army, such as flags and spears.  Further research is needed to confirm this idea.

d) As a trend during a certain period.  Some swords were also used for ceremonies.

e) To show the swordsmith's skill.

NOTE: Most Ôdachi were used for reason a) and b).

The production of Ôdachi 

Ôdachi are very difficult to produce.  The requirements to make a good Ôdachi are as follows:

a) A lot of steel is needed to produce a Ôdachi and it takes longer to make than a normal sword.  However to make a good Ôdachi it is important to hammer the steel quickly.  This requires great skill from the swordsmith.

b) A Ôdachi is made with teamwork.  Perfect teamwork is required to make a good one.

c) More skill is required in quenching and tempering a Ôdachi than a normal sword.

d) Special facilities are required.  For example the quenching tank must be bigger than that used for normal swords.

e) The method of polishing is different.  Ôdachi need to be hung from the ceiling or placed in a stationary position to be polished, unlike normal swords which are moved over the polishing stones.

How to use Ôdachi

Ôdachi that were used as weapons were too long for Samurai to carry on their waists like normal swords.  There were two methods in which Ôdachi could be carried. One method was to carry it on your back.  This was impractical however, as it was impossible for the Samurai carrying the sword to draw it quickly.  The other method was simply to carry the Ôdachi by hand.  The trend during the Muromachi era was for the Samurai carrying the Ôdachi to have a follower to help him draw it.

Ôdachi swordplay styles focused on downward chops and different wields to that of normal swords. 

The use of Ôdachi in early times

The Ôdachi's importance died off after the Osaka-Natsuno-Jin war of 1615 (battle between Ieyasu Tokugawa and Mitsunari Ishida). Since then it has been used more as a ceremonial piece.  

The two main reasons for losing popularity are:

1. Battles in fields did not occur after 1615.

2. The Bakuhu government set a law which prohibited holding swords above a set length (in Genwa 3 [1617], Kwanei 3 [1626]  and Shoho2 [1645]).

After the law was put into practice, Ôdachi were cut down to the shorter legal size.  This is one of the reasons why Ôdachi are so rare.

Ôdachi were no longer of practical use, but were still made as offerings to Shinto shrines.  This became their main purpose.  Due to the amount of skill required to make one it was considered that their awesome appearance was suitable for praying to the Gods.  

Conclusion 

The Ôdachi is no longer a practical weapon, but a few still survive to this day.  Handed down from era to era as a sacred tool or treated as a legend, the sword used by the Gods in mythology.  The Ôdachi has attracted many people throughout history and, hopefully, will never lose its attraction.

The majority of information presented here was obtained from the Atsuta Jingu (Nagoya) Ôdachi exhibition catalogue (no ISBN), kindly translated by H.Kakuta.  Thanks to Guido Schiller for pointing out the difference between Ôdachi and Nodachi.