Round iron plate of grey colour decorated in low relief (sukidashi-bori) on the face with sea waves (both layered waves, seigaiha, and rough waves, araumi), sago palm (cycas revoluta, sotetsu), presumably orchid leaves (ran) - five of them - hanging from the above, and  reeds (ashi), and on the back with waves (seigaiha only), rocks, chrysanthemums (kiku), clove (chori), reed, and presumably orchid leaves - three of them - hanging from the above. The kozuka-hitsu-ana was probably cut later. The plate is lacking the raised rim, typical for the kamakura-bori school. Muromachi period.  Dimensions: Height: 76.8 mm, width: 76.1 mm, Thickness at seppa-dai: 3.3 mm, at rim 2.0 mm. Height of nakago-ana: 29 mm. Weight: 82.4 g. NBTHK certificate № 402152: Hozon - "Worthy of preservation". A similar (most probably the same) tsuba is illustrated and described at Butterfield & Butterfield. IMPORTANT JAPANESE SWORDS, SWORD FITTINGS AND ARMOR. Auction Monday, November 19th, 1979. Sale # 3063 under lot № 66. It describes the piece as following: “Kamakura bori work of the Muromachi period. Round thin plate with some small iron bones in the edge. Carved with design of plants (sego palm) rocks, and waves on the face. The back has half of two chrysanthemums, waves, clove, and sego palm leaves. The kozuka-hitsu has been added and later enlarged. A good typical example without the rim most have. Diameter: 7.7 cm., thickness 2.5 mm. Estimated price $100-200":

Iron tsuba of round form pierced with design of paulownia (kiri) in a circle in positive silhouette (ji-sukashi), details carved in low relief (sukidashi-bori). Hitsu-ana were cut later and then both plugged with lead or pewter. Brown patina. The most unusual characteristic of this tsuba is its 'positiveness': the absolute majority of Kamakura-bori tsuba are of ko-sukashi type, i.e. with small openings, presenting the motif in negative silhouette. Kamakura-bori school. Muromachi period (ca. 1450). Size: Height: 85.1 mm, width: 84.8 mm, thickness at seppa-dai: 3.2 mm, at rim: 2.8 mm. Weight: 79.1 g. A similar tsuba is presented at Japanese Swords and Sword Fittings from the Collection of Dr. Walter Ames Compton. Part I. Christie's, New York, March 31, 1992, page 11, №3: "A Kamakura-bori tsuba. Muromachi period, ca. 1450. The round iron plate is pierced with an openwork design of a paulownia crest (kiri-mon), the surface details of which are carved in low relief. The design is repeated on the reverse. The edge is slightly raised  and the rim has some iron bones. 78 mm x 77 mm x 3.5 mm. Hakogaki by Sato Kanzan, dated summer 1973."

Iron tsuba of six-lobed (mutsu-mokkō-gata) form, with six wild boar's eye shape (inome) openings (sukashi). Hitsu-ana and the entire perimeter of tsuba have typical for this school raised rim. Lobes are decorated with landscape motifs in low relief carving (sukidashi-bori). On the obverse: A hut under a full moon, Shinto shrine gates (torii) with pines and a full moon, rocks, a large pine tree, and a temple (pagoda) surrounded by rocks and waves. On the reverse: waves, fishing boat, wild gees in flight under full moon, maple, hexagon (tortoiseshell, kikko) with a dot inside and a dot outside (inclusion/exclusion symbol), and chrysanthemum (the last two may be family crests, mon). Kamakura-bori school. Late Muromachi period (1514-1573). Height: 64.2 mm, width: 74.3 mm, Thickness at seppa-dai: 3.2 mm, at rim 2.6 mm. Weight: 62.8 g (light). NBTHK old green certificate №561: Tokubetsu Kicho  - "Extraordinary Work". A look-a-like tsuba can be found at the Compton Collection, part II, pp. 14-15, №17, though his tsuba is more massive (80 x 84 x 4 mm). NBTHK paper says that the motif is Hakkei (八景), i.e. "Eight Views," so several interpretations are possible (the original Chinese ones, Omi Hakkei, etc.).  However, most likely it is the 'Eight views of Omi' (近江八景  - 'Omi Hakkei'). Why the artist selected a 6-lobed form for depicting 8 views remains unclear, and thus we are in our right to raise the question whether the motif is indeed Hakkei. The term Omi hakkei (eight views of Omi) refers to painting or print sets which illustrate life on the shores of Lake Biwa in Omi (now Shiga Prefecture). The model for such paintings came from China, where, from the eleventh century onward, painters had produced eight views of the Hsiao and Hsiang lake areas of Hunan Province. The themes, which follow the original Chinese models, are: geese descending to land, returning fishing boats, clearing rain, a snow-covered evening landscape, the autumn moon, night rain, a temple bell at evening, and the glow of sunset. Japanese artists have also used the eight-theme approach for other parts of country - including cities - and applied it to subject matter other than landscapes. [Merrily Baird. Symbols of Japan. Thematic motifs in art and design. Rizzoli international publications, Inc., 2001, page 308-9]. Japan Encyclopedia by Louis Frédéric also mentions Omi Hakkei as "Eight landscapes of Omi", and states that this theme was often cited in poetry after 1500. It is likely that the tsuba in focus is designed under the influence of the theme popularity in the 16th century. The theme was effectively exploited by prominent ukiyo-e artists Suzuki Harunobu and Utagawa Hiroshige in the 18th and 19th century, respectively. These are the eight scenes of the theme (see Wikipedia):

• Returning sails at Yabase (矢橋の帰帆) - Yabase. Yabase is an old harbour on the east side of the lake. Near the Tokaido, it was used for a shortcut to Otsu by boat.
• Evening glow at Seta (勢多（瀬田）の夕照) - The Chinese Bridge at Seta. The long bridge across the Seta was used by the Tokaido. In the background the "Fuji of Omi", the Mikamiyama. It is just above 400 m, but indeed well visible.
• Autumn moon at Ishiyama (石山の秋月) - Ishiyama Temple. The Ishiyamadera was located on a hillside next to the Seta River. It got his name form the strange rocks on which it is built, partly on supporting beams. A hut at the upper end of the site allows a view of the lake, and the moon.
• Clear breeze at Awazu (粟津の晴嵐) - Awazuhara. Awazu is well known for its pine wood, Awazu-ga-hara.
• Evening bell at Miidera (三井晩鐘) - Mii-dera. Miidera temple was built in the 8th century. Its famous bell is one of the "Three bells of Japan", the other two being those at Byoodo-in, Uji and at Jingoji, Kyoto.
• Evening rain at Karasaki (唐崎の夜雨) - Karasaki Shrine. Karasaki is a small cape with a single large pine tree, a hitsu-matsu.
• Wild geese returning home at Katata (堅田の落雁) - Ukimido. Alighting geese cannot be seen always, however the little temple near Katata in the square hōkyō-style, detached from the lakeside, connected by a bridge. The first part of the name uki is the same as in Ukiyo-e, meaning floating. Midō means temple.
• Evening snow at Hira (比良の暮雪) - Hira Mountains. The Hira mountains on the west side of the lake experience the hard winter, when the winter monsoon brings much snow from the continent.

In any case, as a conservative, I say that it is a landscape motif and a late Muromachi period work, rather than Omi hakkei motif and a mid-Muromachi work.

Six-lobed iron tsuba in a form of three ginkgo tree leaves (icho), separated with three small triangular openings (ko-sukashi). Leaves have raised rim and decorated with various family crests (mon) in low relief carving (sukidashi-bori). On obverse: bamboo stems and leaves, knotted geese, paulownia (kiri), plum blossom (ume), and ivy. On reverse: pine needles and cone, maple leaf (kaede), bamboo, stylized plum blossom, and Genji-mon. Black patina. Kozuka hitsu-ana is original, with raised rim. Copper sekigane. Kamakura-bori school. Late Muromachi period (ca. 1550). Size: Height: 81.1 mm. Width: 90.0 mm. Thickness at seppa-dai: 3.3 mm. Weight: 120.4 g.

Shingen school tsuba with woven wire pattern. Iron core, woven brass wire. Height: 72.5 mm; Width 69.8 mm; Thickness at seppa-dai: 4.0 mm. Weight 88.8 g. Late Muromachi, 16th century. SOLD http://varshavskycollection.com/shingen-tsuba/

Iron tsuba of round form with design of iris and snowflake in openwork (ko-sukashi or small cut-outs) outlined with brass wire. Three concentric rows of brass dots (ten-zōgan), with a brass circular line inside the innermost row of dots (missing on the back). Hitsu-ana is not outlined with brass wire, which let us suppose that it was cut out at a later date. Iron and brass. Ko-sukashi and ten-zōgan technique. Mid Muromachi period (1454-1513). Height: 74.0 mm, Width: 73.6 mm, Thickness: 3.0 mm.

NBTHK certification of 1968: "Kicho". Condition is relatively poor: rust, missing inlay, scratches.

While representation of the snowflake is rather standard, the meaning of the other cut-out design was initially less clear. Similar symbol was found at (1) "Kokusai Tosogu Kai, International Convention & Exhibition, September 24-25, 2005, The Frazier Historical Arms Museum, Louisville, Kentucky, USA"; on page 21 there is a photograph J-6 of a ko-tosho tsuba with "iris theme openwork"; (2) Japanese Swords and Tsuba from the Professor A. Z. Freeman and the Phyllis Sharpe Memorial collections. Sotheby's, London, Thursday 10 April 1997; page 11, lot 6 - a ko-katchushi tsuba of early Muromachi period fith "simple design of stylized iris". In both sources the symbol is explained as 'iris" (kakitsubata).

Iron tsuba of round form with design of diamond-shaped family crest (waribishi-mon) in openwork (sukashi). Bevelled, raised rim. Kozuka-hitsu-ana plugged with tin or lead. Ko-Katchushi school. Early Muromachi period: Early 15th century (Oei era). Size: Height: 89.3 mm. Width: 89.0 mm. Rim thickness: 4.3 mm. Center thickness: 2.9 mm. Provenance: Sasano Masayuki Collection, № 41: "In this tsuba, a family crest incorporating four lozenges sits upright on the right side of the nakago-ana. The straight lines of the lozenge add substance and power. Initially, the crest creates confusion regarding the age, yet the overall impression is one lacking in vigor and probably dates rather later than Nanbokucho period".  

Iron tsuba of round form decorated with chrysanthemums, pine cones and needles, pampas grass, vines, cherry blossoms, and wild geese in brass inlay (suemon-zōgan) and pierced with designs of water clover (denjiso) and half bellflower (or karahana) to the left and to the right of nakago-ana as well as double bars above and below nakago-ana (possibly with the meaning of number 2 or ordinal 2nd). Most probably the sukashi elements here are the family crests (mon). Unsigned. Ōnin school. Muromachi period; 15th or 16th century. Height: 82.1 mm; Width: 80.9 mm; Thickness at seppa-dai: 2.4 mm NBTHK # 2003827: Tokubetsu Hozon Tosogu Kanteisho (特別保存刀装具鑑定書) - "Extraordinarily Worthy of Preservation".

Iron tsuba of round form decorated with two boar's eyes (inome) and two dragonflies (tombo) in small openwork (ko-sukashi) outlined with brass wire. The plate also decorated with 2 to 5 concentric circular rows of brass dots (nail heads) in ten-zōgan. Center of the plate outlined with the inlaid circular brass wire. The inlaid metal is of red-ish hue, so it may be copper, and not brass. The surface has remnants of lacquer. Ōnin school. Mid Muromachi period, middle of 15th century. Dimensions: Diameter: 90 mm, thickness: 3.2 mm. Notes regarding design: "According to various sources, the dragonfly (tombo) is emblematic of martial success, as various names for the insect are homophones for words meaning "victory". The dragonfly is also auspicious because references in the Kojiki and Nihongi link it in both name and shape to the old kingdom of Yamato."  [Merrily Baird. Symbols of Japan. Thematic motifs in art and design. Rizzoli international publications, Inc., 2001, p. 108]. "The dragonfly (tonbo), was also called kachimushi in earlier times, and due to the auspicious literal meaning "victory bug" of the characters of this word it became a popular theme on sword fittings." [Iron tsuba. The works of the exhibition "Kurogane no hana", The Japanese Sword Museum, 2014, p. 13]. Two other cutouts - in the form of what in European tradition symbolizes the heart, on the top and in the bottom of tsuba disc - may have two different explanations. The most usual one, inome - "Heart-shaped pattern, which is said to go back to the shape of a wild boar's eye" [Markus Sesko. Encyclopedia of Japanese Swords. Print and publishing: Lulu Enterprises, Inc., 2014.]. This understanding is shared by Robert Haynes [Robert E. Haynes. Study Collection of Japanese  Sword Fittings. Nihon Art Publishers, 2010.] and elsewhere, with an exception of Okabe-Kakuya [Okabe-Kakuya. JAPANESE SWORD GUARDS. Museum of Fine Arts, Boston. In cooperation with the department of Chinese and Japanese art; - 1908, p. 14], who provides the illustration of inome-shaped cut-outs with the following explanation: " The tsuba shown in Fig. 13 approaches a square form with rounded corners and is perforated with Aoi decoration. But this book was written long time ago, when people even at MFA might not know enough... The same interpretation of the said heart-like symbol (aoi leaf) is given at Helen C. Gunsaulus. Japanese sword-mounts in the collection of Field Museum. // Publication 216, Anthropological Series, Volume XVI; Chicago, 1923; p. 54: "This mokkō-formed tsuba recalls the aoi form, perforated as it is with the four aoi leaves." It is possible that the "wild boar's eye" theory was developed by later scholars.   There is also a theory, supported by Graham Gemmell, saying that: “In simple terms Onin works are decorated Ko-Katchushi tsuba. … But, not content with iron alone, they began to decorate it with what was, in the early Muromachi period, a rare and valuable metal, brass. The Onin workers cut the design into the iron, using narrow channels, cast the brass, piece by piece, and then hammered it into the iron plate as though they were putting together a jigsaw. When complete the tsuba would be black lacquered exactly as the plain iron ones had been, the brass shining dully through it in a way that fulfilled the goal of shibui or restrained elegance.” [Tosogu. Treasure of the samurai. Fine Japanese Sword Fittings from The Muromachi to The Meiji Period, by Graham Gemmell. // Sarzi-Amadè Limited, London, 1991. An exhibition held in London from 21st March to 4th April, 1991]. The following illustration from Helen C. Gunsaulus. Japanese sword-mounts in the collection of Field Museum. // Publication 216, Anthropological Series, Volume XVI; Chicago, 1923; pp. 43 supports the idea. Helen C. Gunsaulus' description of the dragonfly emblem is as follows: "This motive, the dragon-fly  (akitsu), is generally accepted as a symbol of the kingdom of Japan, and the origin of the idea is traced to the legend recounted in the Kojiki and Nihongo of the Emperor Jimmu's view of the island from mountain top. He is said to have thought the kingdom looked like a dragon-fly touching its tail with its mouth. From this it received its name Akitsu-shima... etc."  

Iron tsuba of slightly elongated round form decorated with design of melon flowers, vines, and leaves in brass flat inlay (hira-zōgan) on both sides. Slightly raised rim (mimi) carved in a way to simulate ring-shaped covering (fukurin). Kozuka hitsu-ana and kogai hitsu-ana both plugged with soft metal (tim or lead). Copper sekigane. Heianjō or Kaga School. Muromachi or Momoyama period, 16th century. Iron, hira-zōgan brass inlay. Round (maru gata) form, diameter 79 mm. Size: 80.3 x 78.4 mm; thickness at seppa-dai: 3.4 mm; at the middle: 3.8 mm; before the rim: 2.4 mm, rim: 2.8 mm. Note on design: though this design resembles family crests with oak and mulberry leaves, I believe it's  a melon flower [see Jeanne Allen. Designer's guide to Samurai Patterns. Chronicle Books, San Francisco, 1990, page 114, №130 "Melon Flowers": Note about the distribution of thickness (niku-oki): "this tsuba has toroid features, niku raises from the rim towards the centre but thins once more out when approaching the seppa-dai" [M. Sesko, "Handbook...", p. 48].

Iron tsuba of round form decorated with inlay of four concentric rows of brass dots or nail heads (ten-zōgan) and a circular brass wire inlay inside the innermost row of dots. Copper sekigane. Muromachi period, 15th or 16th century. Unsigned. Ōnin school. Size: 87.9 x 87.8 x 2.2 mm. Ōnin school got its name from the Ōnin War (応仁の乱 - Ōnin no Ran) - a civil war that lasted 10 years (1467–1477) during the Muromachi period in Japan.

A yamagane  (unrefined copper) ko-kinko tsuba of slightly elongated round form with design of wisteria carved in sculptural relief (nikubori). Copper sekigane. Unsigned. Muromachi period, likely the 16th century.

Size: 74.3 x 71.8 x 3.2 mm.

NBTHK certificate №4003986: Hozon (worthy preservation). In custom wooden box.