Board Thread:Naruto Discussions/@comment-23915152-20180418082757

I hate to contradict the data book if it does indeed say that it's a hidden piece of flint in the teeth, but I'm more inclined to believe it is either a small basic unknown jutsu, part of the actual jutsu itself, or an actual cannon use of the hidden mouth ember that Ibiki used in the anime. Flint doesn't spark, it's just that when struck against steel the flint's edge shaves off bits of the steel that exposes iron which ignites at below room temp which is about 70 degrees F or 21 C when exposed to oxygen in the air. I've seen the anime and read the manga so I've seen the spark that comes from when the teeth are clicked together, but flint doesn't work like that, I think that might have been another tiny bit of inspiration on the part of Kishimoto. One of the early antagonist in Rurouni Kenshin was a member of the Oniwabanshu Onmitsu called Hiotoko who had a bag full of fuel hidden in his stomach with a hose leading to his mouth so that when he squeezed his abdominal muscles it would force the fuel out and he wold click together his teeth..he had no other teeth in his mouth other than the four front teeth top and bottom and were said to be made of flint which would then spark the fuel and allow him to breath fire. When Asuma clicks his teeth together the spark seems to be focused on the front four where the thinnest part of the ash cloud is to allow it to be set off quicker. This is just my theory but it's something that's bugged me since he first used it against Hidan and it was said to be hidden flint that caused the spark, so I think it's not actually flint but the idea may have come from Rurouni Kenshin since Kishimoto did take inspiration from other manga at times. 