San'yo-Onoda City

The sleeper said to have dammed a river.

Netaro Weir, Asa River

01 ／ Takadomari Reclamation

Even City Hall and Onoda Stationstood in the sea of Takadomari Bay.

The Takadomari reclamation was closed off from the sea in 1668 and became 400 chobu of rice fields. The drainage sluice's swinging doors shut at high tide and opened at low tide. The three doors became five in 1857, and the sluice retired in 1989. It is a national Historic Site, and the doors are currently removed.

Sea closed off in 1668; 400 chobu of fields
Five swinging doors (widened in 1857)
Retired from service in 1989
National Historic Site (1996)

02 ／ Sulfuric-Acid Bottles and Ryusan-machi

The bus stop is named Ryusan-machi (硫酸町).Sulfuric-acid bottles were fired at Sarayama.

Once sulfuric-acid production began, making bottles to hold it flourished. Using acid-resistant clay from Dan (旦), potters fired them in Dan kilns from around 1889-90. The saying went, "sulfuric-acid bottles mean Onoda." Iwami-ware potters came each spring and went home in autumn.

Town names: Cement Town, Sulfuric-Acid Town, Gunpowder Town
Fired in Dan kilns from around 1889-90
Onoda Sarayama products (city-designated): sulfuric-acid bottles and 99 items in all

03 ／ Itone Pine Grove

A pine grove where Izumi Shikibu gave birth,so a Hachiman shrine's records say.

The Itone pine grove in Habu is a stand of black pines on a sandbar. The largest has a trunk girth of 293 cm and stands 20 m tall; the oldest trees are estimated at about 200 years. The Habu Hachiman record says the poet Izumi Shikibu gave birth here. Habu has a legend that she ended her life there, and a grave stands.

Black pines, about 11,000 m²
Largest: girth 293 cm, height 20 m
Oldest estimated at about 200 years
City Cultural Property (1990)

Living here

The Asa and Ariho rivers cross reclaimed plains.

about 60,000 people
Shinkansen stops here

Sanyo-Onoda lies in southwest Yamaguchi, bordering Shimonoseki, Ube and Mine. Its whole coastline faces the Seto Inland Sea, and much of its flatland is reclaimed. The climate is mild, with the low rainfall of the Inland Sea. Ryuozan Park has a campground, and Yakeno Beach is the city's only swimming beach. The city formed in 2005 from Onoda and Sanyo.

People living here: 60,326people
Area: 133.09km²
Households: 26,106households
Rent (average for rentals): 41,496yen
Healthcare: 6 hospitals ／ 56 clinics

Area and habitable land at the same scalee-Stat B1101 / B1103

Children waiting for childcare: —17 nurseries and similar
Home purchase subsidy: —
Average annual temperature: —

These 3 items are waiting on a nationwide data source. We do not fill them with estimates.

ACCESS

Where you can go from here.

San'yo-Onoda City in Japan34.003°N 131.182°E

to OsakaSanyo Shinkansen207min

Travel times follow JR西日本「JRおでかけネット」区間時刻表『東海道･山陽･九州新幹線(東京～博多～鹿児島中央) 下り』（https://timetable.jr-odekake.net/line-timetable/1796 ・2026年9月29日のダイヤ）。厚狭に停まる下りの列車は『こだま』だけ（のぞみ・みずほ・さくら・ひかりは『レ』＝通過）。新大阪始発でそのまま厚狭に着く『こだま』は941A（新大阪7:40発→厚狭11:18）・945A（9:32→13:11）・947A（10:37→14:11）・949A（11:37→15:11）・961A（17:37→21:11）・965A（18:37→22:11）・967A（19:37→23:04）の7本。東京・品川・名古屋・京都発で厚狭に着く列車の欄はすべて空。表の全体は $SP/jr-shinkansen-down-20260929.json（下り）・jr-shinkansen-up-20260929.json（上り）に保存 (checked 2026-09-29). They vary by time of day.

Shape

Borders 3 municipalities.

Territory of San'yo-Onoda City

Boundaries: National Land Numerical Information (N03)

North to south

21.0km

宇部市, 美祢市, 下関市

San'yo-Onoda City isthis kind of town.

01In Asa, Sanyo-Onoda, the tale of Netaro tells of a young man who slept three years and three months, dammed the Asa River, and turned the marshy Senchogahara into rice fields. The weir was rebuilt in concrete in 1963 and is now called Netaro Weir (寝太郎堰).
02The flatland around City Hall and Onoda Station is land the Hagi Domain closed off from Takadomari Bay in the Edo period, the Takadomari reclamation. Its drainage sluice, Hama Gochō Karahi (浜五挺唐樋), is a national Historic Site, and its swinging doors are currently removed.
03At Sarayama in Onoda, sulfuric-acid bottles were fired from around 1889-90, and a bus stop still carries the name Ryusan-machi. The Tokkuri kiln, built in 1883, is a national Important Cultural Property, and Himebotaru fireflies glow on Mount Ryuo in early summer.

If something caught your eye, ask the town itself.

San'yo-Onoda City official site ↗Wikipedia ↗