Accession O's parents had been plotting to overthrow King
Hkun Law who succeeded Wareru in 1307. In March 1311, Bala and U Yaing staged a palace coup while Law was out on an elephant hunting trip. Bala's troops killed the king upon his return. (O had two full younger brothers.) During the deliberations, the throne was vacant for at least two weeks, perhaps even longer. Bala finally yielded to his wife's demand, and O ascended the throne on 10 April 1311.
Early reign One of the first acts of his reign was to seek recognition from Martaban's overlord
Sukhothai. The king of Sukhothai gave him recognition with the title of Saw Thin Maung, and sent his daughter
May Hnin Htapi in a
marriage of state.
Break with Sukhothai By 1317/18, O had emerged from his father's shadows. With his northern frontier with
Pinya quiet, he considered challenging Sukhothai. He broke with his overlord six years into his reign. (Chronicles do not state why O, married to a Siamese princess, suddenly decided to challenge his nominal overlord. According to
Cœdès, King
Ram Khamhaeng died "shortly before 1318", not 1299 as reported by the
Chinese records. If Cœdès's conjecture is correct, O may have decided not to pledge allegiance to Khamhaeng's successor
Loe Thai.) At any rate, he attacked Sukhothai's western vassals, and went on to seize Lamphun region south of
Chiang Mai by 1320/21. Emboldened by success, he next targeted Sukhothai's southern possessions on the
Tenasserim coast, taking
Tavoy (Dawei) and
Tenasserim (Taninthayi) in the following dry season. He was so pleased with the victory that he built a palace in the Tenasserim town, and spent time in his newly acquired region. He was succeeded by his younger brother
Saw Zein. ==Family==