Iron tsuba of round form decorated with eight roundels – circular emblems of flowers and/or family crests (mon) made of cast brass, pierced and chiseled in kebori, and with flat brass inlay (hira-zōgan) of vines or leaves all over the plate. Both hitsu-ana trimmed in brass. Nakago-ana of rectangular form, with copper sekigane. Four positive openwork (ji-sukashi) roundels at 12, 3, 6, and 9 o'clock; and four negative openwork (in-sukashi) roundels with cherry blossom, bellflower, and two variations on suhama theme. Yoshirō school (Kaga-Yoshirō). The Momoyama or early Edo period, late 16th to early 17th century. Size: diameter 81.4 mm, thickness 4.7 mmat seppa-dai, 4.0 mm at rim. Christie's lot description: AN IRON TSUBA; EDO PERIOD (17TH CENTURY). THE DOLPHYN COLLECTION OF SAMURAI ART. The round iron tsuba pierced with roundels of various floral motifs interspersed among scrolling foliage, all inlaid with brass. 8.1 cm. high. Provenance: Pabst Collection (no. 338).

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.

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:

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.

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 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.