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Gohyakugawa

A mutation of Koshihikari.

Pedigree

Skip the diagram and read the list
Norin No.22 → Koshihikari Norin No.1 → Koshihikari Norin No.8 → Norin No.22 Norin No.6 → Norin No.22 Moritawase → Norin No.1 Rikuu No.132 → Norin No.1 Ginbozu → Norin No.8 Asahi → Norin No.8 Joshu → Norin No.6 Sen'ichi → Norin No.6 Rikuu No.20 → Rikuu No.132 Kamenoo No.4 → Rikuu No.132 Aikoku → Rikuu No.20 Koshihikari → Gohyakugawa Gohyakugawa Koshihikari Etsunan No.17 ・ 32.6% Norin No.22 Kinki No.34 Norin No.1 Hokuriku No.4 Moritawase Rikuu No.132 Rikuu No.20 Kamenoo No.4 Aikoku Norin No.8 Kinki No.15 Norin No.6 Kinki No.9 Joshu Sen'ichi Ginbozu Asahi
The diagram shows this variety's own parents and the line that connects it to Koshihikari. Among the descendants only the main varieties are drawn; the other parent of each cross, and every descendant not drawn here, are listed in full below. Faint boxes are unnamed breeding lines.

Parents

Cross combination: コシヒカリ(突然変異)

Descendants

Relations are counted along the shortest line of descent. The rows in the diagram follow the order of crosses, so a variety with more than one path down can sit lower in the diagram than its relation here suggests.

Only one phrase about its origin reads clearly

Line selection from a mutant of Koshihikari

That is the origin as the source gives it. Not a cross: a change that arose inside Koshihikari, found and taken forward as a line. The breeder is named as Suzuki Kiyokazu.

The source is one sheet from the Ministry of Agriculture, Forestry and Fisheries' listing of varietal characteristics of non-glutinous brown rice in agricultural produce inspection. Because it exists for inspectors, it describes the look of the grain in detail.

  • Grain shape: elliptical, slightly smaller than Koshihikari
  • Colour: pale brown, good lustre
  • Bran thickness: thin
  • Longitudinal groove: shallow but conspicuous
  • White core and white belly: few

Some fields could not be read

The sheet is set in two columns, and the pairing of field names with their values would not hold steady on reading. Read twice, some fields gave different pairings.

Breeding site, year of breeding, registration number, maturity class. None of these are written here. Filling an unreadable field with a guess would loosen everything downstream of it, so the fields are left empty.

Where Gohyakugawa was found is talked about often enough. But the only thing this site can draw a line from is what the source says. Common account is not a citation.

There are two sheets for the same variety

Gohyakugawa has two sheets: one for Chiba and one for Niigata. And the field labelled "provenance" reads "Chiba" on the one and "Niigata" on the other.

So that field is the producing prefecture, not the breeding site. Reading one sheet alone, it would have been taken for the breeding site. Having two sheets for the same variety is what settled the meaning of the field.

The description of the grain differs between them as well.

Chiba sheet Niigata sheet
Grain shape elliptical, slightly smaller than Koshihikari rounded elliptical, medium grain
Colour pale brown, good lustre amber, good gloss
Bran thin somewhat thick
Per 1,000 grains 18.1 g 19.8 g

These sheets exist for inspectors, and each was written looking at brown rice grown in that prefecture. The same variety reads differently from one prefecture to the next. Neither is wrong; they are looking at different rice.

The breeder's name, Suzuki Kiyokazu, appears below the title on both sheets in the same way. It is the only thing the two agree on.

A mutation that went the other way on grain size

A number of varieties on this site come from mutations of Koshihikari. Among them, Inochinoichi has a grain weight rated extremely large, while Gohyakugawa is slightly smaller than Koshihikari. Out of the same Koshihikari, grain size swung both ways.

The list of Koshihikari's children gathers the mutation-derived ones in one place.

Sources disagree

Which parent of Koshihikari was the seed parent

The NARO historical document states in words that Norin No.22 was the seed parent and Norin No.1 the pollen parent. Niigata Prefecture, which bred the variety, states the reverse. The diagram follows the historical document; Niigata's account is recorded here. We call neither wrong.

The year of the cross

The NARO documents appear to reproduce the prefectures' original applications for recommended-variety status and give 1945 — and the documents for Honenwase, Hatsunishiki and Yamasenishiki, all from the same cross, give 1945 as well, four in agreement. Niigata's own account says the cross was made in 1944 and that the 1945 planting was skipped for lack of hands. We use 1944 and note the discrepancy.

How the seed parent of Norin No.1 is written

The two spellings appear in the same NARO database, in the pedigree field and in the historical document respectively. We use the pedigree field's spelling and list the other.

How Kamenoo No.4 is written

We follow the NARO database. The commonly seen spelling uses a katakana no; we prefer the spelling we can cite.

On naming

Variety names are proper nouns. We use a name in this language only where a published source for it can be cited; otherwise the Japanese name stands.

What we have not yet confirmed

We have not looked below the top twenty

The site covers the twenty most widely planted varieties of the 2024 crop and the varieties that connect them back to Koshihikari. Many descendants exist below that line; we have not yet verified them against primary sources.

The year Masshigura was crossed

Neither Aomori Prefecture's table of recommended-variety characteristics nor the NARO database gives the year Masshigura (Aokei No.138) was crossed. The cross itself, Ou No.341 / Yamagata No.40, and its adoption as a recommended variety in fiscal 2004 are confirmed from primary sources; the year of the cross is not. For the same reason we do not say which parent was the seed parent. On 8 October 2026 we went back to the breeder's own side. The Masshigura page in the variety database of the Aomori Prefectural Industrial Technology Research Center's Agriculture and Forestry Research Institute carries a heading reading “The origin of Masshigura” — with nothing under it. Of the institute's bulletins, only No.42 (2015) onward are online, and the issue that would hold the breeding report for Masshigura is not among them. So the year of the cross is absent from the breeder's own published material as well.

Sources

The source document is in Japanese.

  1. イネ品種データベース検索システム「越南17号（コシヒカリ）」品種来歴文書 — Institute of Crop Science, NARO ・ primary source ・ accessed 2026-09-10
  2. イネ品種データベース検索システム 交配系譜図「越南17号」 — Institute of Crop Science, NARO ・ primary source ・ accessed 2026-09-10
  3. イネ品種データベース検索システム「北陸4号（水稲農林1号）」品種来歴文書 — Institute of Crop Science, NARO ・ primary source ・ accessed 2026-09-10
  4. イネ品種データベース検索システム 交配系譜図「北陸4号」 — Institute of Crop Science, NARO ・ primary source ・ accessed 2026-09-10
  5. イネ品種データベース検索システム「北陸4号を親とする品種一覧」（全263行） — Institute of Crop Science, NARO ・ primary source ・ accessed 2026-10-01
  6. イネ品種データベース検索システム「越南17号を親とする品種一覧」（全607行） — Institute of Crop Science, NARO ・ primary source ・ accessed 2026-10-01
  7. イネ品種データベース検索システム 交配系譜図「近畿34号（水稲農林22号）」 — Institute of Crop Science, NARO ・ primary source ・ accessed 2026-10-01
  8. イネ品種データベース検索システム 交配系譜図「近畿15号（水稲農林8号）」 — Institute of Crop Science, NARO ・ primary source ・ accessed 2026-09-10
  9. イネ品種データベース検索システム 交配系譜図「近畿9号（水稲農林6号）」 — Institute of Crop Science, NARO ・ primary source ・ accessed 2026-09-10
  10. イネ品種データベース検索システム 交配系譜図「陸羽132号」 — Institute of Crop Science, NARO ・ primary source ・ accessed 2026-09-10
  11. イネ品種データベース検索システム 交配系譜図「陸羽20号」 — Institute of Crop Science, NARO ・ primary source ・ accessed 2026-09-10
  12. コシヒカリのエピソード1 〜交配から系統の育成まで〜 — Niigata Prefectural Government ・ primary source ・ accessed 2026-09-10
  13. 新潟コシヒカリの軌跡 〜誕生から定着に至るまで〜 — Niigata Prefectural Government ・ primary source ・ accessed 2026-09-10
  14. 戦後日本のイノベーション100選「コシヒカリ」経緯 — Japan Institute of Invention and Innovation ・ accessed 2026-09-10
  15. あきさかりの良さを引き出す栽培法 — Fukui Prefectural Government ・ primary source ・ accessed 2026-09-10
  16. ぎふクリーン農業／県産品種 ハツシモ — Gifu Prefectural Government ・ primary source ・ accessed 2026-09-11
  17. 水稲「あさひの夢」の奨励品種採用（研究成果情報） — National Agricultural Research Center, NARO ・ primary source ・ accessed 2026-09-11
  18. コシヒカリのエピソード2 〜奨励品種への採用から〜 — Niigata Prefectural Government ・ primary source ・ accessed 2026-09-10
  19. コシヒカリBLの導入のねらい — Niigata Prefectural Government ・ primary source ・ accessed 2026-09-10
  20. イネ品種データベース検索システム「近畿15号（水稲農林8号）」品種来歴文書 — Institute of Crop Science, NARO ・ primary source ・ accessed 2026-09-16
  21. イネ品種データベース検索システム「近畿9号（水稲農林6号）」品種来歴文書 — Institute of Crop Science, NARO ・ primary source ・ accessed 2026-09-16
  22. 品種登録データベース 品種名検索（品種名のよみ） — Ministry of Agriculture, Forestry and Fisheries ・ primary source ・ accessed 2026-10-01
  23. イネ品種データベース検索システム「越南12号（ヤマコガネ）」品種来歴文書 — Institute of Crop Science, NARO ・ primary source ・ accessed 2026-10-01
  24. イネ品種データベース検索システム「山陰47号（ヤエホ）」品種来歴文書 — Institute of Crop Science, NARO ・ primary source ・ accessed 2026-10-01
  25. 農産物検査における水稲うるち玄米の品種銘柄の特徴（五百川） — Ministry of Agriculture, Forestry and Fisheries ・ primary source ・ accessed 2026-10-02
  26. 農産物検査における水稲うるち玄米の品種銘柄の特徴（五百川・新潟県） — Ministry of Agriculture, Forestry and Fisheries ・ primary source ・ accessed 2026-10-08