The book meticulously documents Zen Buddhism's support of Japanese militarism from the time of the Meiji Restoration through the World War II and the post-War period.

Victoria draws from his own study of original Japanese documents, but also uses the publications of Ichikawa Hakugen, a Rinzai-priest and a scholar who taught at Hanazono University in Tokyo.

[14]Robert Aitken writes: All of us owe gratitude to Victoria, to James Heisig, and John Maraldo for their book, Rude Awakenings: Zen, the Kyoto School, and the Question of Nationalism, and to the scholars who are publishing a series in Zen Quarterly, the English language journal of the Soto Sect, disclosing the collusion of their sect in Japanese expansionism prior to and during World War II.

[15]Ton Lathouwers, Chán-teacher in the Netherlands, in relation to Zen at War mentions Hisamatsu's impossible question, "What will you do when you cannot do anything, when all your best intentions and great endeavour are invested to no avail whatsoever, when all you do is doomed to fail?

[17] In response to Zen at War, Ina Buitendijk started a campaign to receive apologies from leading parties within the Japanese Zen-schools:[18] On 8 January 2000 a letter arrived from a lady who lives in the Netherlands.

It reported that her husband, from the age of six until he was nine, was confined in a concentration camp in the Dutch East Indies during World War II by the Japanese army [...] Not only he himself has suffered a great deal, the lady says, but also his distress has had, and still has, a great impact upon his family [...] The main reason the Dutch lady raised the question is that she had read Brian Victoria's book Zen at War and felt herself betrayed by the war-time words and deeds of the founder of the Sanbô Kyôdan Yasutani Haku'un Roshi, who repeatedly praised and promoted the war.

For the offense caused by these errant words and actions of the past master, I, the present abbot of the Sanbô Kyôdan, cannot but express my heartfelt regret.

Kemmyō Taira Sato states that Victoria's criticism of D. T. Suzuki is misplaced since he did not support Japanese militarism in his writings: In cases where Suzuki directly expresses his position on the contemporary political situation—whether in his articles, public talks, or letters to friends (in which he would have had no reason to misrepresent his views) – he is clear and explicit in his distrust of and opposition to State Shinto, rightwing thought, and the other forces that were pushing Japan toward militarism and war, even as he expressed interest in decidedly non-rightist ideologies like socialism.

[22]Victoria himself quotes critical remarks by Suzuki on the war and the support given to it by the Zen-institutions: "[T]hey diligently practiced the art of self-preservation through their narrow-minded focus on 'pacifying and preserving the state'.

He extracts the words and deeds of Japanese Buddhist leaders from their cultural and temporal context, and judges them from a present-day, progressive, Western point of view.

This inherent support made it possible to effect a transmission from authoritarian imperialism to democracy: [O]ne of the most significant and most overlooked explanations lies in the fact that the concepts of popular sovereignty and human rights have deep roots in Japanese culture.

Specifically, it attempts to demonstrate that Buddhism, as one of the "Three Treasures" of Japanese culture, is inherently antithetical to the authoritarian socio-political structures that have periodically been imposed on the people of Japan.

Bodhin Kjolhede, dharma heir of Philip Kapleau, says: Now that we've had the book on Yasutani Roshi opened for us, we are presented with a new koan.