These records have been commercially available in print since 19891967, when it was published under the title Haisen no Kiroku (敗戦の記録, lit. Records of Defeat) by Hara Shobo. This included materials spanning from March 1944 to late 1945. Here is an Amazon.jp link to a version2005 edition.
A related publication is the Sugiyama Memos (杉山メモ), written by General Sugiyama Hajime, published also by Hara Shobo in 1967. This is detailed recordsrecord of meetings at the highest level of Japanese leadership between 1940 and 1944, when Sugiyama was Chief of the General Staff.
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 materials published in the aforementioned sources. The "truth", however, is a complex matter of interpreting such materials and as such debate continues.