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.

Iron tsuba of round form with design of ginger and double diamonds (myoga-ni-nigaibishi) in openwork (sukashi), details carved in kebori technique. Slightly rounded square rim. Copper sekigane. Shoami school. Early Edo period: Late 17th century (Kanbun/Enppo era). Height: 80.1 mm. Width: 79.8 mm. Rim thickness: 5.0 mm. Center thickness: 4.7 mm. Provenance: Sasano Masayuki Collection, № 110.  

Shingen school (or style) tsuba of round form with iron core and web, covered with a thin brass plate decorated with star-shaped punch marks. The rim of tsuba is a brass nawame-fukurin. Between the central brass plate and the rim there is woven wire of brass and copper in a basketweave pattern. Both hitsu-ana have raised rim. Traces of oxidation. Unsigned. Edo period, 18th century. Size: Height: 88.4 mm, Width: 86.6 mm, Thickness at seppa-dai: 4.6 mm. Weight: 132.4 g. Robert E. Haynes in his "Study Collection of Japanese Sword Fittings. Nihon Art Publishers, 2010" on p. 117 says: "Brass outer plate of round shape. This tsuba has an iron core tsuba of spoke form as made by Saotome school, ca. 1500. There are brass plates on either side connected to the rim by woven brass and shakudō wire. The wire has been hand drawn, which is very difficult. The hitsuana are brass lined and the rim has a brass cover. This type of tsuba is referred to as a Shingen tsuba. This is a reference to Takeda Shingen Harunobu (1521-1573), the great and famous daimyō." For reference see the MFA collection. A look-a-like tsuba is illustrated in Compton Collection, vol. 2, p. 26-27, №52: More details and examples can be found at: http://varshavskycollection.com/shingen-tsuba/

Iron tsuba of round form inlaid with brass, copper, and shakudō wire fastened to the surface with metal staples (mukade-zōgan); Scalloped brass inlay around the rim. Early Edo, 17th century. Height: 84.8 mm; Width 84.8 mm; Thickness at seppa-dai: 3.7 mm. Weight 161.6 g. Design is thought to resemble a centipede. "Centipede-like inlay (mukade zogan) of alternating iron and brass staples produce an appearance that was particularly favored by Takeda Shingen (1521-1573), one of the most powerful warlords of his time. The centipede is sacred to Bishamon (God of War) and especially propitious for a warrior. Shingen type, 16^th century.” [The Peabody Museum collection of Japanese sword guards with selected pieces of sword furniture, by John D. Hamilton. Photographs by Mark Sexton. Salem, MA, 1975.] See also: http://varshavskycollection.com/shingen-tsuba/

Shimizu-Jingo tsuba with a dragon and vajra (on reverse) motif. Unsigned. Possibly, 3rd or 4th master of Shimizu-Jingo family in Higo province. Iron. Low relief carving. Edo period, 1700's. Height: 75.4 mm, Width: 72.2 mm, Thickness at seppa-dai: 4.0 mm

Kozuka with seven insects (fly, grasshopper, bee, butterfly, dragonfly, firefly, and cricket) and grass with dewdrops motif. Shakudō, flush gold inlay (hira-zōgan). 95.2 (H) x 13.7 mm (W). Mid Edo period (Late 17th - early 18th century, Genroku era 1688-1703). Unsigned. Kaga school. A look-a-like kozuka (with five insects) is illustrated at Japanese Sword Fittings. A descriptive catalogue of the Collection of G.H. Naunton, Esq., completed and illustrated by Henri L. Joly, - 1912 on plate XXIX, №691 [LIB-1389 in this Collection] with the following description at page 54: "Shakudō, inlaid with butterfly, dragon-fly, grasshopper, locust and another insect, gold." See also tsuba TSU-0211 in this collection:    

Iron tsuba of slightly elongated round form with design of wild geese and drops on pampas grass (masashino) in openwork (sukashi). Rounded rim. Copper sekigane. Owari school. Early Edo period: early 17th century (Kan-ei era). Height: 78.8 mm. Width: 76.3 mm. Rim thickness: 6.1 mm. Center thickness: 6.4 mm. Provenance: Sasano Masayuki Collection, № 169. A description of musashino symbolism can be found at Symbols of Japan by Merrily Baird [Merrily Baird. Symbols of Japan. Thematic motifs in art and design. Rizzoli international publications, Inc., 2001]: Musashino - "the plain of Musashi - a large expanse in the Tokyo area, was celebrated in poetry for the grasses that grew there before the recent era of industrialization... The use of Musashino themes was particularly common in the Momoyama and Edo periods". Pampas grass with dew drops and wild geese in flight collectively provide strong autumnal connotation.  

Iron tsuba of round form with design of double crossbar and two family crests (hikiryo-ni-kamon) in openwork (sukashi). Squared rim. Copper sekigane. Owari school. Early Edo period: Late 17th century (Kanbun / Enppo era). Height: 80.9 mm. Width: 80.8 mm. Rim thickness: 5.0 mm. Center thickness: 4.6 mm. Provenance: Sasano Masayuki Collection, № 172: "A paulownia and a clover are diagonally opposite two crossbars. This expressive design suggests a Higo origin, but the iron and the finish are certainly of the Owari school. Work of this nature may have been influenced by Hayashi Matashichi (1613-1699)."