When he discovers the criminal gang responsible, he leaves behind his life as a maths teacher and joins them, looking for a chance to take his revenge.

"[7] Comparing the novel to Isaka's sequel novel Bullet Train (translated to English years ahead of its preceding novel), Malissa said that "'3 Assassins' goes deeper, so there’s more psychological exploration of the characters, which adds nuanced sophistication to the action.

"[7] The Unseen Library lauded the novel as "another awesome read from Kotaro Isaka that takes readers on a wild and exciting journey to Japan’s outrageous underworld of assassins.

[10] Contrasted to Bullet Train, The New York Times lauded "3 Assassins [a]s a sparser, sourer thriller, its slow pursuit distending across Tokyo and leaving plenty of time for dread", concluding that as a "surrealist fable disguised as a crime novel, “3 Assassins" feels like a fever dream that makes sense when you’re in it, but whose strange contours linger long after you wake up.

"[11] A manga adaptation drawn by Hiroto Ida was published from 2008 to 2010 on Kadokawa Shoten's Young Ace magazine, and later collected in three volumes.