| # | player | result | 1 | 2 | 3 |
|---|---|---|---|---|---|
| 1. | Iwamoto Kaoru | 2-0 | W+R | ||
| 2. | Fujisawa Hosai | 1-1 | W+F | ||
| 3. | Nakamura Yutaro | 0-2 | B+R |
| date | black | white | result | #mv | sgf |
|---|---|---|---|---|---|
| 1945-07-23,24,25 | Hashimoto Utaro | Iwamoto Kaoru | W+5 | 295 | sgf |
| 1945-08-04,05,06 | Iwamoto Kaoru | Hashimoto Utaro | W+5 | 240 | sgf |
| 1945-11-11,12,13 | Hashimoto Utaro | Iwamoto Kaoru | B+3 | 245 | sgf |
| 1945-11-15,16,17 | Iwamoto Kaoru | Hashimoto Utaro | B+3 | 295 | sgf |
| 1945-11-19,20,21 | Hashimoto Utaro | Iwamoto Kaoru | B+R | 147 | sgf |
| 1945-11-23,24,25 | Iwamoto Kaoru | Hashimoto Utaro | B+R | 231 | sgf |
The match was being played in Hiroshima. The first game in the center. The second game, at the insistence of a police officer, in the outskirts. On the third day of the second game the atomic bomb was dropped (according to Iwamoto, between White 106 and Black 107). Windows were broken, stones were shattered, but the players set the position up again and continued. Hashimoto won. Afterwards, the match was suspended for three months, until after the end of the war.This match ended in 3-3. The rules prescribed a final game, with 4.5 komi, but the match was not continued. The following year, a best-of-three playoff was played.
| date | black | white | result | #mv | sgf |
|---|---|---|---|---|---|
| 1946-07-31,08-15,16,17 | Hashimoto Utaro | Iwamoto Kaoru | W+5 | 305 | sgf |
| 1946-08-19,20,21 | Iwamoto Kaoru | Hashimoto Utaro | B+6 | 274 | sgf |
Iwamoto Kaoru won with 2-0.
As Honinbo, Iwamoto took the name Honinbo Kunwa.