If the teaser site didn’t give it away or the registration of the domain name “Valkyria3.jp,” then this will. SEGA uploaded their TGS line up with a few “coming soon” sections in their line up. But if you change the image URL extension from .gif to .jpg, Wala! 戦場のヴァルキュリア3, aka Valkyira Chronicles 3 appears.
The listing didn’t include a platform though. Hopefully we will find out more details on September 16th. Be sure to check out SEGA’s stage events on the 16th as well.