Hi All,
This may help the quest for information. IMVHO, Kujang and Kudi have similar shapes, but the kujang is mainly a cut-n-thrust implement,while the kudi is a tombak or short throwing spear. The Kudi is a traditonal implement found mainly on Java and Madura, while the Kujang is a traditional implement peculiar to the Sunda people of West Java ( mainly in the area known as Parahyangan). I believe that the Kujang was first produced circa 13-14C., during the Pajajaran kingdom. With regard to the tang, I must admit that in my very limited experience, I've only ever seen round ones on old pieces ( new ones tend to have rectangular ones). That is not to say , rectangular ones weren't used in old pieces

With respect to the piece in the picture, I have seen similar shapes in the following collections:
- Yayasan Pangeran Sumedang, Sumedang, West Java, Indonesia.
- Peninggalan Sejarah Sukapura, Tasikmalaya, West Java, Indonesia.
Hope it helps.