Mounting styles (koshirae)

What a koshirae is

The koshirae (拵) is the complete dress of a blade: the hilt (tsuka) with its ray skin (same) and its wrap (ito), the menuki underneath, the guard (tsuba), the fuchi and kashira, the washers (seppa), the blade collar (habaki) and the scabbard (saya) with its mouth (koiguchi), its retaining knob (kurigata) and its end cap (kojiri).

Loose fittings are called tōsōgu (刀装具) and are collected in their own right, sometimes above the blade they once dressed. The NBTHK judges the blade, the complete mounting and each fitting in separate examinations: a well documented katana can arrive with three papers.

Loose fittings: tōsōgu

The metal and lacquer pieces that dress a blade are called tōsōgu (刀装具): the guard, the collar and cap of the hilt, the ornaments under the wrap, the retaining knob and the end cap of the scabbard, and the collar that seats over the edge. Each piece was collected — and still is — on its own, regardless of which blade it once dressed, and the NBTHK examines them separately from the blade and from the complete mounting: a signed tsuba can hold a paper the sword it once belonged to never earned.

The tsuba (鐔) is the guard: it protects the hand, balances the sword and, by the Edo period, is above all a calling card. It is worked in iron (tetsu), in shakudō (a copper-gold alloy patinated to a bluish black), in shibuichi (copper and silver, grey) or in gold; it is decorated by carving the metal in relief (katachibori) or by piercing it clean through (sukashi), and its outline — round, four-lobed mokko-gata, mallow-shaped aoi-gata — and the design of its rim (mimi) help attribute it to a school: ko-tōshō and ko-katchūshi among the oldest, Owari and Kyō-sukashi for their geometric openwork, Higo for its flat iron and inlaid wire, Nanban for motifs of foreign influence. The central hole (nakago-ana) fits over the tang, and copper wedges (sekigane) true it to each blade.

The fuchi (縁) and the kashira (頭) are the collar and cap of the hilt, almost always matched; the menuki (目貫) are the pair of ornaments left under the wrap, one under the palm and one under the fingers, which also keep the hand from slipping. When the fuchi-kashira, the menuki and sometimes the kozuka and the kōgai — the small utility knife and the skewer kept in the scabbard of a travelling sword — share the same theme and the same metal, the set is called mitokoromono (三所物), «the three-place things». The Gotō school, goldsmiths to the shogunate from Gotō Yūjō in the fifteenth century, worked generation after generation in shakudō nanako (a granulated ground) with gold relief; in Edo, the city's own carvers (machibori), such as Yokoya Sōmin and his followers of the Nara school, moved away from that canon toward more narrative, naturalistic subjects.

The kurigata (栗形) is the knob that projects from the scabbard near its mouth, through which the sageo cord is threaded to fasten the sword to the obi so it cannot fall as it is drawn. The kojiri (鐺) caps and protects the tip of the scabbard, in the same metal, lacquer or horn as the rest of the set. The habaki (鎺) is the one fitting shared with nothing: it is made to fit a single blade alone, seats exactly over the edge above the machi and acts as a stop against the mouth of the scabbard (koiguchi), so the blade sits firm without the edge touching the lacquer; it is usually copper or shakudō, and on the finest pieces it has two layers, a core (shitagane) sleeved in a gilt outer skin. The seppa (切羽) are the paper-thin washers set on each side of the tsuba so the assembly sits tight and does not rattle.

The NBTHK judges the tsuba and a tōsōgu set at its own Hozon and Tokubetsu Hozon levels, just as it does a blade: looking at the metal, the crispness of the carving, the signature if there is one, and the condition. Many tsuba and menuki of great name now circulate without any sword at all, collected for what they are — small sculpture in metal — with a market of their own, apart from that of the blades they once dressed.

A shirasaya is not a mounting

A shirasaya (白鞘) is a scabbard and hilt of bare wood, almost always honoki (Japanese bigleaf magnolia), with no lacquer, no tsuba, no ray skin and no wrap, carved to fit that blade exactly and no other. It is not a poor mounting: it is a case. The wood is stable, low in acid and lets the steel breathe, so the blade rests without rusting; the finish is wax, not lacquer. Some shirasaya have no mekugi at all and hold by friction.

When the blade moves into its case, the good mounting is kept assembled around a tsunagi (繋ぎ), a wooden filler blade. So «with shirasaya» in a listing means the piece comes with a storage case, not that it has two mountings. And since the NBTHK rejects mountings without a tsuba as a rule — aikuchi aside — a shirasaya never receives a mounting paper.

Tachi-koshirae: the sword that hangs

The tachi mounting (太刀拵) carries the sword slung from the obi edge down, held by two hangers (ashi or obitori) fixed to the scabbard. Its pommel is not a kashira but a kabutogane, heavier and cap-like; the scabbard carries bands (semegane) and a metal end fitting. The hilt often curves more than the blade itself and sometimes takes two mekugi.

Its ceremonial variants are the showiest in the field: court kazari-tachi, hyōgo-gusari-no-tachi with chain hangers, itomaki-no-tachi with the wrap continued over the upper scabbard to protect it from armour. They dominate from the late Heian period to Nanbokuchō and survive afterwards as ceremonial and shrine mountings.

Uchigatana-koshirae and its two relatives

The uchigatana-koshirae (打刀拵), also called buke-zukuri, is the mounting taken for granted on a katana: thrust through the obi edge up, held by the kurigata and its cord (sageo), it allows drawing and cutting in one pull instead of the two movements a tachi demands. It is the ordinary form from the Muromachi period on, when combat moved from mounted duels to masses of infantry.

Tenshō-koshirae (天正拵): the sober version that took shape in the Tenshō era (1573-1592), a counter-current to the loud Momoyama mountings. A drum-shaped hilt, waisted in the middle (ryūgo-gata), a black-lacquered horn kashira with the wrap passing over it, a leather-covered scabbard lacquered black — sometimes faded to reddish brown — and a plain tsuba of iron or yamagane. It is a fighting mounting, and that is why it is prized.

Handachi (半太刀): «half tachi». It borrows tachi fittings — a kabutogane instead of a kashira, bands (semegane) on the scabbard and a tachi-type end fitting — but drops the hangers (ashikanamono), so it is not slung: it goes in the sash. In its basic form the blade sits edge down, tachi fashion, though examples mounted edge up like a katana exist; Western sources usually give only that second variant. It was born in the transition from tachi to uchigatana and stayed in fashion from the late Muromachi period into the early Edo period.

Higo and Satsuma: two provincial manners

Higo-koshirae: it grew under the patronage of Hosokawa Tadaoki, known as Sansai (1563-1646), daimyō and tea master, in Higo province (Kumamoto, with his retirement at Yatsushiro). It joins the austerity of the tea room to practical swordsmanship: a shorter hilt, a scabbard of ray skin or covered in leather, a retaining hook (kaerizuno) and iron fittings with flat piercing, often inlaid with gold or silver wire. From that circle come the four schools of Higo kinkō: Hirata (Hikozō), Hayashi (Matashichi), Nishigaki (Kanshirō) and Shimizu (Jingo).

Satsuma-koshirae: tied to the fencing schools of Satsuma, Jigen-ryū and the Yakumaru branch. A very long hilt, straight in profile, heavy and rough iron fittings, a small tsuba often pierced with two little holes so it could be lashed to the hilt, a thick scabbard and a kaerizuno.

Beware the label «satsuma rebellion koshirae»: it is not a Japanese term but a Western collectors' tag. What it describes are cheap, coarse mountings assembled from old parts — sections of scabbard used as hilts, iron washers for menuki, hemp cloth wraps — often on flawed or cut-down blades, and far more common on wakizashi than on katana. Specialists identify them with okashi-tō, lent swords issued to non-samurai troops in the late Edo period, rather than with the Satsuma Rebellion of 1877.

Aikuchi, daishō and guntō

Aikuchi (合口): a mounting with no tsuba, in which the fuchi and the mouth of the scabbard meet flush; hence the name, «mouths that meet». It comes from the koshigatana and from the Kamakura period on it is the elegant mounting for a tantō. It is the only form the NBTHK accepts without a guard.

Daishō (大小): «large and small», the pair of long and short blade with fittings en suite. It became popular at the end of the Muromachi period, with examples from the late sixteenth century; wearing it was reserved to the samurai class in 1683, and for formal dress the bakufu prescribed a black scabbard and wrap with white ray skin. Two blades by the same smith are uncommon and not required: what makes a daishō is the matched pair of mountings.

Guntō (軍刀): military mountings. The kyū-guntō, Western in cut with a knuckle bow, was regulation from 1872 to 1934. The shin-guntō Type 94 (1934) returns to a hilt of ray skin and wrap, with cherry-blossom fittings and a metal scabbard with two hangers; the Type 98 (1938) drops the second hanger and simplifies the rest. The Type 95 (1935), for non-commissioned officers, carries a machine-made blade with a groove and a stamped serial number, and a hilt first cast in painted metal and, by the end of the war, made of wood. The navy used the kai-guntō. Many old blades were remounted in guntō during the war, so the mounting says nothing about the age of the blade; and the NBTHK criteria, which admit post-Meiji work only if signed and well made, leave industrial blades outside.

What makes a mounting «period»

The NBTHK publishes its examination criteria for mountings (text in force since 19 May 2015), and they are the working definition of «period» at Hozon level:

Date of the mounting	What is required
Momoyama or earlier	that it show the features of its time and have documentary value, even with defects and repairs
Edo	good state of preservation and documentary value
Meiji onward	that it respect traditional technique and be of artistic quality

The same text yields consequences that surprise a beginner: a rewrapped hilt does not disqualify if it harmonises with the lacquer and the fittings; a missing kozuka or kōgai is accepted and noted on the paper; and a fitting with a doubtful signature can pass if the ensemble holds together, again with a note. A mounting without a tsuba, on the other hand, is rejected except for aikuchi, and foreign-made mountings are not examined. Tokubetsu Hozon asks for better work, few repairs and good condition.

Outside shinsa, «period koshirae» is the seller's estimate. What can be checked is something else: that the ensemble is coherent — lacquer, fittings and wrap in the same register — that the blade fits its own scabbard, and that there is a mounting paper or at least one signed, datable fitting. Without that, the date of a mounting is an opinion, not a fact.