Hi Fernando,
no luck on the ethnographic forum
. Found a picture of a Burmese Trident, and very nice it is too. Obviously the prong cross section is not round but is dated 18th C.
The Sai,
the 3 pronged dagger/defensive weapon is almost a hand held trident ....interestingly it is suggested it originated in Indonesia...or thereabouts. The trident as a spearhead or hand held 'implement' makes perfect sense for the island communities where fishing is so important. Afterall medievel farm implements were mounted on shafts and used in battle.
".........The sai is known to have been used in other parts of Asia before its arrival on Okinawa, such as India, China, Indonesia, Siam and Malaysia. Early evidence suggests Indonesia or the neighbouring area as the sai's point of origin. In Malay the sai is known as a tekpi or Indonesia language as chabang (also spelled cabang or tjabang, meaning branch) and is thought to derive from the Indian trishula. The chabang quickly spread through the rest of Indo-China and may have reached Okinawa from one or more of these places simultaneously........."
Regards David