How does Hashirama break Tsukuyomi?

[Chazzi]

I'm going by canon. Tsukiyomi's function is to cause mental stress and break the spirit, and Sasuke broke it with his sheer desire to kill Itachi.

Nothing is perfect, everything has a weakness. Itachi said this, so you better accept it.

No where in the manga is it stated that you can break tsukiyomi by having a strong mental fortitude.

 

[UltimateDeadpool]

No where in the manga is it stated that you can break tsukiyomi by having a strong mental fortitude.

It was shown in the manga. Sasuke's desire to kill Itachi was so strong that he overcame Tsukiyomi's effects. It was his mental fortitude that allowed him to do so.

"Sasuke is cornered by the eternal hell created by the "Mangekyou Sharingan"...!!

Perhaps on account of his deep hatred towards his brother, Sasuke manages to beat the "Mangekyou Sharingan", whose abilities are way superior to the ones of a normal "Sharingan"...!!" ~ 3rd Databook

Databook also states that Tsukiyomi works by causing mental stress and breaking their resolve. So if you have a strong mind, strong willpower, you can overcome those effects.