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 almost round form with a brass outlined circular opening (sukashi) in the bottom adorned with the Myriad Treasures [takaramono, 宝物] and winter motifs inlaid in cast brass (suemon-zōgan); hitsu-ana possibly cut later, both plugged with shakudo, nakaga-ana fitted with copper sekigane. According to Merrily Baird^*) (2001), the symbolism of Myriad Treasures “is associated with the Seven Gods of Good Luck, who carry them in a sack”. Among the treasures, which are said to ensure prosperity, long life, and general good fortunes, are (reading clockwise from the top):

1. Sake set [shuki, 酒器], namely flask, ladle, and cups
2. Cloves [choji, 丁子]
3. Purse of inexhaustible reaches [kinchaku, 巾着]
4. Magic mallet [kozuchi, 小槌]
5. Key to the storehouse of the Gods [kagi, 鍵]

Then, Pine, Moon, and Bamboo (see below);

7. Rhombus, or Lozenge (hosho, 方勝), with the second ideograph meaning victory.
8. Sacred (or wish-granting) gem, or jewel [hōju, 宝珠]
9. Hats of invisibility [kakuregasa, 隠れ笠]

The Myriad Treasures is carried by the Seven Gods of Good Luck (a.k.a. the Seven Lucky Gods or Seven Gods of Fortune [shichifukujin, 七福神], who are transported by the Treasure Ship [takarabune, 宝船] during the first three days of the New Year. Pine, Moon, and Bamboo: bamboo [take, 竹] and pinecones [matsukasa, 松笠], or pine [matsu, 松] – two of the Three Friends of Winter [shōchikubai, 松竹梅] – symbolize fidelity, fortitude, steadfastness, perseverance, and resilience. The third ‘friend’  – plum, [ume, 梅] – in this case replaced by the Moon [tsuki, 月] – large (11 mm) circular opening at 6 o’clock; the three small carved dots represent the dewdrops. The other side is decorated with an arabesque (karakusa) of cloves and vines, with carved dots (dewdrops) along the rim. The overall New Year / Winter connotation of the tsuba is clear. The prominence of the Moon conveys purity, coldness (sadness/loneliness), and slenderness – the inherent qualities of a samurai. H: 93 mm x W: 90 mm, thickness 4.2 mm at the centre, slightly tapered towards the rim. *) Merrily Baird. Symbols of Japan: Thematic motifs in art and design. — NY: Rizzoli international publications, 2001. Seller’s description: École Heianjo - Début Époque EDO (1603 - 1868). Nagamaru gata en fer à décor incrusté en hira-zogan de laiton de tama, choji, jarre à saké et des attributs de Daikoku (maillet, chapeau d'invisibilité et sac de richesse) et de branches de choji de l'autre côté et ajourée en kage-sukashi d'un cercle. H. 9,2 cm

Iron tsuba of round form with a butterfly (left) and dragonfly (right) design in openwork (sukashi), outlined with brass wire. The thin plate is also decorated with five concentric circular rows of brass dots (nail heads) in ten-zōgan; brass wire outlines the centre of the plate. School: Ōnin ten-zogan. Late Muromachi period, 16th century. Diameter: 88 mm, thickness at seppa-dai: 3.1 mm. Another tsuba of similar design, Tōshō school, is illustrated in this collection; see TSU-0353.2018. The design is referenced in LIB-1359.2017 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, item 37: "pierced with two large formalised butterflies..."

Iron tsuba of round form decorated with design of sea waves in low relief carving (kebori) and pierced with design of cherry blossom in negative silhouette (in-sukashi) and water wheel in positive silhouette (ji-sukashi). The solid portion of the plate has a shallow groove just before the edge. Copper sekigane. School attribution is unclear. Unsigned. Momoyama period, 16th - 17th century. Dimensions: Height: 70.3 mm, width: 71.1 mm, thickness at seppa-dai: 4.4 mm, at rim 4.1 mm. Provenance: Robert E. Haynes, Mark Weisman. This is what shibuiswords.com says about this tsuba:

"A very unusual iron plate tsuba. The solid plate is carved with waves on both sides. A cherry bloom in sukashi, lower left, and the right third of the plate in openwork with design of a water wheel. The rim with some iron bones. The hitsu-ana is original but the shape may have been slightly changed. One would expect this to be the work of the early Edo period, but the age of the walls of the sukashi would suggest that this is a work of the middle Muromachi period. This must be the forerunner for the Edo examples we see of this type of design." (Haynes)

I managed to find a look-a-like tsuba in Haynes Catalog #5, 1983, pp. 20-21, №44: "Typical later Heianjo brass inlay example. Ca. 1725. Ht. 7 cm., Th. 4.5 mm., $100/200". We see that the  plate design of both tsuba is the same, and the only difference is the trim. It would be logical to assume that both pieces were made at about the same time, rather than 225 years apart. To be fair, let's accept that they were made in Momoyama period.