別々 べつべつ Betsubetsu
The boundary of Shiraoi and Tomakomai, Iburi region, Hokkaidō
Ainu spellings: Pet-pet, Per-pet
A name of a shape repeated across Hokkaidō. The readings divide over whether the doubling is pet 'river' twice or per 'split' before pet.
Location
42.6157, 141.3729 · Coordinates: OpenStreetMap Nominatim, 2026-09-10, on 別々川. Open in OpenStreetMap
Referents
- river The Betsubetsu River, which has long marked the boundary between Shiraoi and Tomakomai and formerly between the Yūfutsu and Shiraoi trading districts
Analyses
pet-pet
ベツベツ ‘river river’ received readingProponent: 定説
Nagata Hōsei writes that the river winds west and then east so that it seems almost to be a different water, and names it for that. Chiri Mashiho reads pe-pe 'water water' and explains it as a place where pools gather; readings pe-pet 'water river' and pe-un-pet 'river with water' combine the two.
Objections
pet is a dictionary word; what the reading offers is a repetition with no landform behind it.
per-pet
ペレベツ ‘split river’ proposedProponent: zenibako_trek（小樽銭函地名歴史研究会） (zenibako_trek (Otaru Zenibako Place-Name and History Society))
Obihiro, also called Oberiberi, is read o-per-pere-p 'place split at the mouth', and the author reads Betsubetsu on the same model.
Evidence
- morphological pattern
The words e-pet-pet-ke 'squid' and o-pet-pet-ke 'torn clothing' show that per-per can shift in sound to petpet.
- topography
Rivers called Bebetsu tend to meet in low ground and run in several strands. Matsuura recorded of the Bebetsu in Biei that its dozens of branch channels lie like a net. Even where river works have straightened them, the ground was formerly deltaic. Matsuura's river map draws Betsubetsu as a delta.
- parallel place names
Names of the same shape occur widely: Benbe in Toyoura, Bebetsu in Biei, Pepenai in Kyōgoku, Henbenai in Teshio, Beberui in Furano.
Both parts are dictionary words in the senses used and the braided course fits. The article states that the recorded spellings of Betsubetsu, Benbe and Bebetsu all differ and that whether the names share a meaning is unresolved.
Attestations
- ベベツ / ベンベツ / ベシベシ / ベシベツ / ベツベツ / ペッペッ map Edo to Meiji 秦蝦夷島図（ベベツ）; 伊能大図（ベンベツ）; 間宮河川図（ベシベシ）; 高橋蝦夷図（ベシベツ）; 今井測量原図（ベツベツ）; 松浦山川図（ベツベツ）; 道庁実測切図（ペッペッ）
The author compares the spellings for Betsubetsu, Benbe in Toyoura and Bebetsu in Biei, and reports that they sound alike yet differ in every case, so that whether the three names mean the same thing is not settled.
zenibako_trek…