What are the marks on Index-tan's left eye? In the Toaru Majutsu no Index specials, Index-tan is shown to have some marks on her left eye. However, she did not have any on the 'main anime'.  



What is the significance of these marks?
If it was not explained anywhere, are there any speculations as to what it might mean?
According to some attendees at an
Index II x Oreimo talk session in December 2010, someone from the Index
staff said there that it was intended to look like Kenji Ohtsuki's face
paint.



It is simply the result of a play on words without any significance:


In Japan, とある魔術の禁書目録 (Toaru Majutsu no Index) is
often referred to as 禁書 (kinsho) in short.
Ohtsuki is the vocalist/lyricist for the Japanese band
筋肉少女帯 (Kinniku Shōjo Tai),
which is often shortened as 筋少 (kinshō).