PewDiePie mentioned Bushido, the Soul of Japan by Inazo Nitobe 1 times

Last but not least, I read--uh, I was so fascinated by the whole Samurai and I wanted to learn more about Samurai so I read "Bushido: The Soul of Japan". For anyone that wants to learn more about Japanese culture and the history of it, I think Bushido is a great starting point.

— PewDiePie