The chrysanthemoid (kiku-gata) iron plate with polished surface decorated with arabesque (karakusa) and paulownia (kiri) leaves and flowers in brass, copper and silver flush inlay (hira-zōgan) on both sides. Some of the inlay goes over the edge. Kozuka- and kogai-hitsu-ana are filled with lead plugs. Sekigane of copper. Chrysanthemum and paulownia are the symbols of imperial family. The face is signed: Izumi no Kami to the right of nakago-ana, and Yoshiro on the left; the back is signed Koike Naomasa. His signed work is considered by many experts to have been made-to-order only. The original wooden box (tomobako) with inscription (hakogaki) signed by Dr. Kazutaro Torigoye and dated Showa 39 (1964). The late Muromachi or Momoyama period, 16th century. Dimensions: 89 mm x 84 mm x 3.6 mm; Weight: 170 g. Hakogaki lid: Yoshirō  kikka-gata Hakogaki lid inside: Iron, signed on the omote: Izumi no Kami – Yoshirō; on the ura: Koike Naomasa. Kikka-gata, pronounced maru-mumi, two hitsu-ana, karakusa, and kiri design in brass, silver, and suaka hira-zōgan. Height 8.5 cm, thickness 3.5 mm. Herewith I judge this work as authentic. On a lucky day in July of 1964. Torigoe Kōdō [Kazutarō] + kaō According to Robert Haynes [Catalog #7, 1983; №32, page 42-43] "This full form of the signature is seen very rarely". His example, illustrated in that catalogue, measures: height = 86 mm, thickness at seppa-dai = 3.75 mm and signed Izumi no Kami Yoshiro on the back and Koike Naomasa on the face. The further description of his specimen by Robert Haynes:

"Early signed example of the work of Koike Naomasa. The kiku shape iron plate is well finished. The flush inlay is brass, for the scroll work on both sides, with the leaves and kiri mon in brass, copper and silver with strong detail carving. Some of the inlay goes almost over the edge, which is goishi gata. The large hitsuana are plugged in lead with starburst kokuin surface design. [...]The face is signed in deep bold kanji: Koike Naomasa; the back is signed: Izumi no Kami, on the right and Yoshiro on the left. There are one or two small pieces of inlay missing. Sold by Sotheby London, Oct. 27, 1981, lot 368. Height = 86 mm, thickness (seppa-dai) = 3.75 mm, (edge) = 4 mm."

Another similar example presented at: "Tsuba" by Günter Heckmann, 1995, №T55 — "Designation: Koike Naomasa. Mid Edo, end of the 17th century. Iron, hira-zogan in brass, copper, silver and shakudo, katakiri-bori. Tendrils and leaves. 87.0 x 78.0 x 4.0 mm." Reference: Japanische Schwertzierate by Lumir Jisl, 1967, page. 13. [SV: Actually, his tsuba is signed Izumi no Kami  Yoshiro on the back; and Koike Naomasa on the front, exactly as Robert Haynes's tsuba. Dating this tsuba Mid-Edo, 17th century may be considered a misattribution]. More details regarding the Yoshirō tsuba. 

Round tsuba of iron; well forged thin plate decorated with a rudder (kaji) and an oar, or paddle (kai) with a water drop, executed in a combination of negative (in-sukashi) and positive (ji-sukashi) openwork. It may be Ko-Tōshō (old Tōshō) or just Tōshō school, without a 'Ko'. The characteristics of the plate point toward an older piece, however the combination of negative and positive silhouettes pulls the date of manufacture in an opposite direction. Muromachi period. Height: 90.0 mm. Width: 89.0 mm. Rim thickness: 2.1 mm. Center thickness: 2.3 mm. Nakago-ana: height = 29 mm, width = 8.8 mm. A rudder and an oar design is classified by John W. Dower as "Sailing vessels and gear": "Unlike many other motifs, sailing vessels and sailing gear failed to collect an interesting lore or to develop levels of meaning." Merrily Baird does not say anything about these symbols. Yuzuri Okada says: "Ships, sails, rudders, etc. also supply motive of the same class as wheels." He does not provide us with the description of the motive supplied by the wheel. The same motif is used on Ōnin tsuba in this collection:

A very large and very thin iron tsuba of round form decorated with design of formalized butterfly and dragonfly in openwork (sukashi). The characteristics of the plate resemble those of Kamakura period ko-tōshō tsuba. However, the design seems too 'modern' to me, but it's hard to tell; it may be a late Muromachi or Momoyama period work. Tōshō or Ko-Tōshō school (or a Katchushi). Muromachi period. Dimensions: 99.6 x 100.5 x 2.1 mm. This is what Jim Gilbert says about old tsuba:

"Traditionally the old iron plate tsuba are classified into Ko Tosho (old sword smith), and Ko Katchushi (old armor maker) styles. It is sometimes difficult to justify attribution of a given tsuba to the Tosho or Katchushi category. Generally guards with raised rims or relatively complex designs tend to be assigned to Katchushi. This is basically a convention we follow out of habit and convenience." [...] "In Token Kai-Shi part six, Articles by Akiyama Kyusaku, Robert Haynes comments: "…from 1300 to 1400 over 150,000 MOUNTED swords were made in Japan for export alone. This means that over four tsuba a day were made for 100 years. This would mean that at least 3000 persons were making nothing but tsuba, let alone all the other fittings needed to complete these swords. With sword smiths, fittings makers and all the other artists need to complete a sword for export, at least 10,000 sword artists were working together, in any one of these hundred years."

Reference to design can be found at "Japanese Swords and Tsuba from the Professor A. Z. Freeman and the Phyllis Sharpe Memorial collections" / Sotheby's, London, Thursday 10 April 1997; p. 18-19, lot № 37: "A Kamakura-bori Tsuba, Momoyama Period. ...pierced with two large formalised butterflies..." Reference to design in this collection: TSU-0319.  

Two ymagane tsuba (daisho) with chiseled diaper pattern of waves. The larger tsuba (dai) is of mokkō form with a wide (4.6 mm) polished rim (fukurin?). Water spray is realized in copper ten-zōgan. Size: 75.0 x 71.6  x 3.2 (center), 4.0 (rim) mm. Copper sekigane. The smaller tsuba (sho) is of oval form, without a rim. No inlay. Size: 53.2 x 45.5 x 4.1 mm. Ko-kinko school. Muromachi period. In Kokusai Tosogu Kai; 5th International Convention & Exhibition, 2009 on page 51 under № 5-U8 there is a piece from George Gaucys collection, described as follows: Unsigned Tachi-Kanagushi tsuba, Yamagane base. Nami (wave) motif. Circa: Muromachi period (15th century). 6.88 x 6.81 x 0.45 (rim), 0.36 (center). The classic wave form is typically seen in Muromachi period tosogu. The patina is rich and rustic, which presents history and warmth. This tsuba may be interpreted as either tachi-kanagushi or ko-kinko work. Early tachi tsuba were symmetrical in design and also not very sophisticated, Design elements filled in up to seppadai as the waves do in this tsuba. There is a simple fikurin of the same metal and it is flat to the plate. On the ko-kinko side, the crests of the waves show more complexity than tachi works and less symmetry. A very intriguing tsuba from late Muromachi period."

Circular form tsuba made by a mirror-maker, i.e. kagamishi. Cast yamagane plate with design of six persimmons on their peduncles surrounded by leaves. Slightly raised rounded square rim. Hitsu-ana is brutally cut later in time. Copper sekigane. Early Muromachi period (1393-1457) or earlier. The inscription on the box reads: "Kamakura or Muromachi Period. Yamagane Tsuba". Dimensions: 81.9 x 81.6 mm; thickness at seppa-dai 2.8 - 3.0 mm, rim 3.4 mm.