Nice reply.but I don't agree with you, the way deidara mentioned it seemed as if it was a special form of training he took just to counter the sharingan. If the method you spoke of is what deidara was using he could have just trained to sense chakra. Why go through the trouble of training a specific eye when there is much easier and more useful method?
No, Deidara can only counter sharingan genjutsu which is no near the level of Tsukuyomi, Kotoamatsukami, Izanagi and Izanami. Besides, his left eye is still weak in countering genjutsu considering he was slow to react to Sasuke's punch. In this scan, you shall notice Deidara realizing there is a sharingan user close to him which normally gives him time to react and counter if its a genjutsu, but he couldn't anything which is why there was no reaction. :yeah:
deidara's slow reaction was as a result of overconfidence, carelessness and exhaustion. Sasuke didn't catch deidara in genjutsu as shown in the page after that. In other words it dosen't prove that deidara is weak at countering genjutsu.
