| Japan Open Golf Championship | |
| Location: | Ibaraki, Osaka, Japan |
| Establishment: | 1927 |
| Course: | Ibaraki Country Club (West Course) |
| Org: | Japan Golf Association |
| Tour: | Japan Golf Tour |
| Format: | Stroke play |
| Month Played: | October |
| Aggregate: | 265 Shaun Norris (2021) |
| To-Par: | −19 as above |
| Current Champion: |  Aguri Iwasaki |
| Map: | Japan#Japan Osaka Prefecture |
| Map Label: | Ibaraki CC |
| Map Relief: | yes |
| Map Size: | 200 |
| Coordinates: | 34.8239°N 135.5417°W |
The is Japan's national open golf championship. Founded in 1927, it is one of the oldest professional golf tournaments in Japan.[1]
The Japan Open is one of the three richest tournaments on the Japan Golf Tour, with a prize fund of ¥210 million in 2022. Between 1992 and 2021 it was the tour's designated "Flagship event" for the purposes of the Official World Golf Ranking, with a minimum winner's points allocation of 32 points.
The winner also receives an invitation to the following year's Open Championship.
| Year | Winner | Score | To par | Margin of victory | Runner(s)-up | Winner's share (¥) | Venue | |
|---|---|---|---|---|---|---|---|---|
| 272 | −8 | 2 strokes | 42,000,000 | Ibaraki (West) | ||||
| Taiga Semikawa (a) | 270 | −10 | 2 strokes | 42,000,000 | Sanko | |||
| 265 | −19 | 4 strokes | 42,000,000 | Biwako | ||||
| Yuki Inamori (2) | 275 | −5 | 1 stroke | 31,500,000 | Murasaki (Sumire) | |||
| 285 | +1 | 1 stroke | 42,000,000 | Koga | ||||
| 270 | −14 | 2 strokes | 40,000,000 | Yokohama (West) | ||||
| Yuta Ikeda (2) | 272 | −8 | 1 stroke | Takumi Kanaya (a) | 40,000,000 | Gifuseki | ||
| 275 | −5 | 3 strokes | 40,000,000 | Sayama | ||||
| 275 | −13 | 1 stroke | 40,000,000 | Rokko Kokusai (East) | ||||
| 270 | −10 | 1 stroke | 40,000,000 | Chiba (Umesato) | ||||
| 274 | −10 | 3 strokes | 40,000,000 | Ibaraki (East) | ||||
| 292 | +8 | 1 stroke | 40,000,000 | Naha | ||||
| 282 | −2 | Playoff | 40,000,000 | Takanodai | ||||
| 271 | −13 | 1 stroke | 40,000,000 | Aichi | ||||
| 282 | −6 | Playoff | 40,000,000 | Musashi (Toyooka) | ||||
| Shingo Katayama (2) | 283 | −1 | 4 strokes | 40,000,000 | Koga | |||
| Toru Taniguchi (2) | 283 | −5 | 2 strokes | 40,000,000 | Sagamihara (East) | |||
| 277 | −7 | 3 strokes | 40,000,000 | Kasumigaseki (West) | ||||
| 282 | −2 | 2 strokes | 24,000,000 | Hirono | ||||
| 285 | −3 | 4 strokes | 24,000,000 | Katayamazu (Hakusan) | ||||
| 276 | −8 | 2 strokes | 24,000,000 | Nikko | ||||
| 271 | −9 | 4 strokes | 24,000,000 | Shimonoseki | ||||
| 277 | −7 | 4 strokes | 24,000,000 | Tokyo | ||||
| Naomichi Ozaki (2) | 281 | −3 | 1 stroke | 24,000,000 | Takanodai | |||
| 298 | +10 | 2 strokes | 24,000,000 | Otaru | ||||
| 283 | −5 | 1 stroke | 24,000,000 | Oarai | ||||
| 286 | +2 | 1 stroke | 24,000,000 | Koga | ||||
| 282 | −2 | 2 strokes | 24,000,000 | Ibaraki (West) | ||||
| 277 | −7 | 1 stroke | 16,200,000 | Kasumigaseki (East) | ||||
| Masashi Ozaki (5) | 270 | −18 | 13 strokes | 18,000,000 | Yokkaichi | |||
| 281 | −3 | 5 strokes | 18,000,000 | Biwako | ||||
| Masashi Ozaki (4) | 277 | −11 | 5 strokes | 18,000,000 | Ryugasaki | |||
| Tsuneyuki Nakajima (4) | 290 | +2 | Playoff | 18,000,000 | Shimonoseki | |||
| Tsuneyuki Nakajima (3) | 281 | −7 | 2 strokes | 18,000,000 | Otaru | |||
| Masashi Ozaki (3) | 274 | −6 | 1 stroke | 10,000,000 | Nagoya (Wago) | |||
| Masashi Ozaki (2) | 288 | +4 | 1 stroke | 10,000,000 | Tokyo | |||
| Isao Aoki (2) | 279 | −9 | 1 stroke | 10,000,000 | Arima Royal | |||
| Tsuneyuki Nakajima (2) | 284 | −4 | 1 stroke | 10,000,000 | Totsuka (West) | |||
| 285 | −3 | 2 strokes | 10,000,000 | Higashinagoya | ||||
| 283 | −5 | 2 strokes | 10,000,000 | Ranzan | ||||
| 281 | −7 | Playoff | 8,000,000 | Rokko Kokusai | ||||
| 277 | −7 | 5 strokes | 8,000,000 | Musashi (Toyooka) | ||||
| 280 | E | 1 stroke | 8,000,000 | Nihon Line | ||||
| 296 | E | 1 stroke | 8,000,000 | Sagamihara (East) | ||||
| 285 | −3 | Playoff | 8,000,000 | Hino | ||||
 Seve Ballesteros (2) | 281 | −7 | Playoff | 10,000,000 | Yokohama (West) | |||
| 284 | E | 1 stroke | 10,000,000 | Narashino | ||||
| 288 | −4 | 1 stroke | 10,000,000 | Central (East) | ||||
| 278 | −10 | 3 strokes | 8,000,000 | Kasugai (East) | ||||
| 279 | −13 | 1 stroke | 6,000,000 | Central (East) | ||||
| 278 | −10 | 2 strokes | 4,500,000 | Ibaraki (West) | ||||
| 1972 | 278 | 1 stroke | Otone (East) | |||||
| 1971 | 282 | Playoff | Aichi | |||||
| 1970 | 282 | 1 stroke | Musashi (Sasai) | |||||
| 1969 | Hideyo Sugimoto (2) | 284 | 1 stroke | Ono | ||||
| 1968 | 284 | 1 stroke | Sobu (East & Middle) | |||||
| 1967 | 282 | 3 strokes | Hirono | |||||
| 1966 | 285 | 1 stroke | Sodegaura | |||||
| 1965 | 284 | 1 stroke | Miyoshi | |||||
| 1964 | 288 | 1 stroke | Tokyo | |||||
| 1963 | Toichiro Toda (2) | 283 | 2 strokes | Yokkaichi | ||||
| 1962 | 287 | 2 strokes | Chiba (Umesato) | |||||
| 1961 | 289 | Playoff | Takanodai | |||||
| 1960 | Haruyoshi Kobari (2) | 294 | 5 strokes | Hirono | ||||
| 1959 | 296 | Playoff | Sagamihara | |||||
| 1958 | Torakichi Nakamura (3) | 288 | 4 strokes | Takanodai | ||||
| 1957 | 288 | 6 strokes | Aichi | |||||
| 1956 | Torakichi Nakamura (2) | 285 | 8 strokes | Kasumigaseki (West) | ||||
| 1955 | Koichi Ono (3) | 291 | 5 strokes | Hirono | ||||
| 1954 | Yoshiro Hayashi (2) | 293 | 3 strokes | Tokyo | ||||
| 1953 | Son Shi-Kin (2) | 291 | 1 stroke | Takarazuka | ||||
| 1952 | 279 | 11 strokes | Kawana Hotel (Fuji) | |||||
| 1951 | 288 | 3 strokes | Naruo | |||||
| 1950 | 288 | 1 stroke | Abiko | |||||
| 1942–1949: No tournament due to World War II | ||||||||
| 1941 | 290 | 3 strokes | Hodogaya | |||||
| 1940 | Tomekichi Miyamoto (6) | 285 | 2 strokes | Tokyo (Asaka) | ||||
| 1939 | 287 | 5 strokes | Hirono | |||||
| 1938 | 294 | 3 strokes | Fujisawa | |||||
| 1937 | 284 | 7 strokes | Sagami | |||||
| 1936 | Tomekichi Miyamoto (5) | 293 | 1 stroke | Naruo | ||||
| 1935 | Tomekichi Miyamoto (4) | 296 | 8 strokes | Tokyo (Asaka) | ||||
| 1934 | No tournament due to flood damage | |||||||
| 1933 | 294 | 9 strokes | Kasumigaseki (East) | |||||
| 1932 | Tomekichi Miyamoto (3) | 298 | 1 stroke | Ibaraki | ||||
| 1931 | Rokuzo Asami (2) | 281 | 4 strokes | Hodogaya | ||||
| 1930 | Tomekichi Miyamoto (2) | 287 | 19 strokes | Ibaraki | ||||
| 1929 | 298 | 2 strokes | Ibaraki | |||||
| 1928 | 301 | 7 strokes | Tokyo (Komazawa) | |||||
| 1927 | 309 | 10 strokes | Hodogaya | |||||