Six Samurai + Book of Moon + Book of Taiyou

[naikii]

Just a wondering.
If I control 2 Six Samurai, lets say:

The Six Samurai - Kamon and The Six Samurai - Yaichi
(Kamon, Destroy a Set Spell/Trap card on the field)
(Yaichi, Destroy a face up Spell/Trap card on the field)
Both effects have to have another Six Samurai on the field.
I use both effects, I play (on my main phase 1) Book of Moon (1) and change Kamon to Defens face down, the I play Book of Moon (2) and change Yaichi to face down. Then I play Book of Taiyou (1,2) and change both to face up, can I use their effect again?

I know that its says "ONCE PER TURN" but since they gets fliped face down, they dont exist on the table anymore, and then flip them again.

//Am I stupid?

[automatonsleuth]

No, you are correct. Flipping the monsters face-down causes them to become 'reset', they are treated as essentially being new, completely different monsters which have just appeared. Thus, when they are flipped face-up again, there is no reason why they cannot use their effects. The exception to this rule would be "You can only use the effect of CARDNAME once per turn." Under this condition, you could only ever activate that effect once each turn, even if 'CARDNAME' is reset.

[naikii]

Thanks for the answer, have been wondering for a while, founded this site three days ago.
Thanks for a fast reply!