These records have been commercially available in print since 1967, when it was published under the title Haisen no Kiroku (敗戦の記録, lit. Records of Defeat) by Hara Shobo. Here is an Amazon.jp link to a version.
A related publication is the Sugiyama Memos (杉山メモ), written by General Sugiyama Hajime detailing records of meetings at the highest level of Japanese leadership between 1940 and 1944.
More usefully for most people, this is a subject that has been examined in great detail by numerous scholars. Serious academic treatment of the subject generally would cite from the aforementioned source. The "truth", however, is a complex matter of interpreting such materials and as such debate continues.