In the early years of his reign, this former viceroy of Prome (Pyay) was forced to deal with raids from the Shan State of Mogaung as well as the Ming Chinese intrusions into Avan territory (1444–1446).
In the wake of renewed Chinese determination to pacify the Yunnan frontier region, Narapati was able to maintain Ava's control of northern Shan States of Kale and Mohnyin, and gained allegiance of Thibaw.
When the king died, the ministers at Ava first chose Minye Kyawswa's son-in-law and brother-in-law Thihapate who was at the front at Mogaung.
Thihapate was recalled to Ava by ministers to assume the throne, but he declined the offer, declaring that he was neither a son nor a brother of the deceased king.
The ministers then invited Thihathu who arrived at Ava on 11 March 1442,[note 2] and formally ascended to the throne with the reign name of Narapati on 6 April 1442.
While his armies were laying siege to Pinle, the new king was forced to deal with a far larger threat from the north: China.
[5] The Ming Chinese had conquered Yunnan after their campaigns of 1380–1388, but never completely controlled the frontier which was still occupied by several Shan States.
The Chinese were forced to send troops back to the region due to the constant Shan raids into Yunnan by Thonganbwa, the saopha of Mogaung.
(Noted historian of Burmese history, GE Harvey, believes that the military numbers reported during the Ava-Pegu era were an order of magnitude higher.)
Narapati appointed the saophas of Mogaung and Mong Nai (Mone) to watch over Bhamo and returned to Ava.
The Maw Shans, now under the leadership of Thokyeinbwa (Chinese: Si Ji-fa), son of Thonganbwa, moved to the region west of Mogaung, and continued the raids into both Ava and Yunnan territories.
Thihapate's son Min U Ti in alliance with Maw Shan raiders Thokyeinbwa and Thopawbwa (Si Bu-fa) raised a rebellion.
[9] On 12 June 1467 (12th waxing of Waso 829 ME), Narapati was stabbed by his grandson whom he had reproved for a love intrigue with his cousin; the wound was not mortal.