Legality, Practicality, and Gentility
Daishō literally means “big-little,” and refers to the pair of swords worn during the shogunate. “Big” in this pair is the famous sword, the katana, and “little” is the wakizashi, or “companion sword.”
In swordfighting, it’s an odd pair. They’re not meant to be wielded simultaneously (Musashi notwithstanding), nor are they different enough to match the “sword-and-dagger” pairing of the West. It was very much a product of their time and place.
As a legal matter, it was required for samurai to wear two blades, as a symbol of their station. It wasn’t exactly required that a samurai wear the daishō — in fact, photographs taken of samurai just before the end of the shogunate show them wearing katana and tantō — but etiquette made it more practical to wear a wakizashi.
This was because it was common practice for a samurai to remove their katana upon entering a castle or palace, and only carry the wakizashi while inside. This explains why the wakizashi resembles a cut-down katana so much — it’s basically shortened so that you can fight without getting your sword stuck in the ceiling.
That said, it would be a mistake to presume that the katana is exclusively an outdoor sword. Its length (short for a two-handed sword) and manner of wear (in the obi with the edge facing upwards in its scabbard) make it the perfect sword to draw directly into a cut from seiza, the formal sitting position. In fact, I’d argue that this requirement is what makes the katana such an odd duck for a two-handed sword. It’s meant to be as dangerous in its scabbard as it is drawn.
The blade of a katana is single-edged, usually with a gentle curve, and with a thrusting tip more resembling an axe than a rapier. If the blade is properly fitted to its owner, its length is roughly the distance from his crotch to his heel. That they typically run from 26 to 30 inches (66 to 76 cm) is an indication of the lack of diversity in the samurai gene pool.
The blade itself is fairly thick, for two reasons. For one, the katana is primarily a cutting weapon. The blade’s thickness adds felt weight at the point of impact, and the extra material contributes to a unique blade cross-section that assists with edge alignment.
For the other, Japanese armor had improved and the tachi (the katana’s predecessor) was considered too light and flimsy a blade to penetrate it. This is also the reason for the axe-like tip and the slightness of the blade’s curve. A good thrust from a katana can penetrate armor and bone.
As the katana is a two-handed weapon, the handle adds another 10 to 12 inches (30 cm) to the overall length of the sword. The user’s hands are protected by a disk guard. The size of the guard could range from 3 to 4 inches (7.5 to 10 cm) in diameter, depending on the user’s preferences. These guards provide decent hand protection, but don’t lend themselves to the binding that cross guards do.
Pretty much everything I’ve said about the katana is true of the wakizashi, except that the wakizashi blades were 20 to 22 inches (51 to 57 cm), and their handles were shorter, as well.
Gaming the Daishō
As of this writing, Japanese swords have not been added to D&D 5e, but — given D&D’s track record in such things — I fully expect to see them by the time you read this. If they haven’t, the katana can be represented by the longsword’s stat block, with the difference being in the role-play aspect: the standard use of a katana would be two-handed, or paired with the wakizashi if it was paired with anything at all.
The wakizashi would imitate the longsword, but the damage would step down (because it’s lighter and has less leverage) to 1d6 slashing damage one-handed and 1d8 two-handed. Besides being versatile, it would be light.
Thus ends my first entry for Everyday Carry in a Fantasy World. If there’s anything on this subject that’s you’d like to see more of, comment here, or DM my Twitter feed.
If you want learn more about Japanese swords in general, I can recommend The Japanese Sword by Kanzen Satō (translated by Joe Earle).