The General’s Sword
Yamoto rode onto the field surrounded by his comrades in arms. His tactical ability was near-legendary, and his soldiers looked on with admiration as he surveyed the battlefield. Seeing the tattered ranks of the rebels arrayed before him, he knew the coming skirmish would be no challenge. Raising his Tachi high as a signal to the army around him, he gave the order to advance.
The battle was fierce but swift. Laying about with his Tachi, Yamoto killed many, but during his last bout with a foot soldier, his Tachi, weakened through years of harsh use, chipped and almost shattered. He managed to dodge the soldier's counterattack and watched as the soldier was quickly finished off by one of his lieutenants. Examining his Tachi, he knew this was its last battle; he would need another.
A few weeks later, he made it back to the capital. The shogun announced a feast in his honor for all the successful victories he had accomplished during the past year. There was much drinking and laughing, and halfway through, the king announced that he had a new gift for the venerated general. The king summoned the royal swordsmith who came quickly with two men carrying a long parcel.
Raising his voice so everyone could hear, the king addressed the general. “My messengers kept me informed of your progress. After hearing of the loss of your Tachi, I commissioned a new sword made as a replacement.” The retainers held still as the swordsmith unwrapped the parcel, revealing an unusually long sword. “This an Ōdachi. They are incredibly difficult to make but are unmistakable. I figured it a fitting weapon for such a revered general as you.”
Featured Sword: Ōdachi
The larger version of the Tachi, the Katana's predecessor, was the Ōdachi. Meaning “Long Sword”, it commonly reached lengths of 90-100cm or more. There were two main uses of the Ōdachi - war and showmanship. As less is known about the Ōdachi compared to the Tachi, we have to make some educated speculation on how it was likely used.
While a Katana or Wakizashi can be drawn in one smooth stroke that can also be used as an attack, the Ōdachi’s size would have necessitated it being worn on the back, preventing this. It would also limit the Ōdachi’s self-defense proclivity, instead making it more useful as a primary weapon on the battlefield. Some soldiers may have even been accompanied by a retainer whose job was to carry the blade and assist the Samurai in drawing it. One place it would have especially shined is as a horseback weapon - the longer reach offered by the blade would have given the horseman an advantage against foes on foot.
A few Ōdachi were made especially long - some over two metres, with the Norimitsu Ōdachi measuring over 3 and three-quarters metres!. These would have been too impractical for use on the battlefield, so they were more likely created as a showpiece by their forger. When a sword is forged, it is important that the entire blade be heated to the same temperature. While fairly easy today with modern technology, back then it was incredibly difficult, and this difficulty increased with the length. Thus only an expert swordsmith could make a high-quality Ōdachi.
A Symbol Raised High
2 months later, Yamamoto looked out on yet another battlefield. The respite in the capital came to an end all too soon, and it was not long before it was time to return to the countryside. This time, the battle would not be so easy. His scouts had alerted him to the position, composition, and size of the enemy forces a day earlier, and he had dispatched horseman during the night who had been traveling through the wee hours in order to reach a flanking position. They should be just out of sight, with a few men scouting ahead and waiting for his signal.He motioned to his retainer, who unsheathed the Ōdachi and handed it to him. Examining the king’s gift, Yamoto lamented that his days as a fighter were over - the sword at over 3 shakas was too large for combat, but to use another sword would dishonor and offend the shogun. However, as his personal symbol, the sword would do even more damage due to the fear it would drive into his enemies and to the hope it would bestow into his own men. With all the men on both sides looking on, he raised it high for the first time. With a cheer, his men rushed forward.
Fun Fact
Because of their oddity, Ōdachi were used in ceremonies and as offerings to the gods.
Etymology
Ōdachi (おうだち/大太刀 in Japanese) is a synonym of the word Nodachi (のだち/野太刀). Ōdachi means “big Taichi”, and Taichi means “long sword”. So literally, Ōdachi means “big long sword”! Nodachi literally means “field Tachi”.
source https://www.bladespro.co.uk/blogs/news/the-japanese-greatsword-the-odachi