Particular blade shape is known as Hua Tat Khong (concave tip).
The Dah has a lot of significance in Kachin culture and tradition.It is one of the most important tool that helps clear land for agriculture purpose, cut trees to provide timber for building houses and even marriage vows are exchanged with the Dah as a witness.
Katana - There are records of Kachin Nationalists fighting against Colonial Rule with their Dahs.It is possible that few of the Colonial Soldiers might have carried them back into the mainland.
During WWII Kachin Rangers who fought alongside the allied forces against the Japanese occupation of Burma were outfitted with such Dahs.
The Khamptis and Singphos residing in Upper Assam and Arunachal Pradesh carry similar blades.
There is a whole chapter dedicated to such dahs in the book An Illustrated Handbook of Indian Arms.
Also check the following link -http://books.google.co.in/books?id=AZ5G6pTRpXQC&pg=PA205&dq=kachin+Dah&hl=en&sa=X&ei=mGUhT_qpBZGyrAfV5vCYCA&ved=0CDcQ6AEwAQ#v=onepage&q=kachin%20Dah&f=false