Ratings
| Year |
Rank |
Edo |
Dev. |
Games |
| 1925 |
1298 |
1942 | (74) | 7 |
| 1926 |
1346 |
1953 | (72) | 0 |
| 1927 |
1335 |
1965 | (67) | 6 |
| 1928 |
1318 |
1973 | (67) | 10 |
Rating table notes
|
| Biographical data |
| Name: Okker, I.H. |
| Born: |
| Died: |
|
| |
| References |
| Books |
| Di Felice, Chess Results, 1921-1930, page 333 |
| Thulin, Name index to CTC, page 193 |
| |
