If we consider the history of Siam of the late 1620s in its entirety, in retrospective YamadaNagamasa was no more than one of many pawns on the chessboard maneuvered by a man, Phya Sriworawong (aka Phra Ong Lai), who stopped at nothing to become king of Siam. By 1628, he had somehow managed to earn the trust of King Song Tham, and when the monarch was approaching death, Phya Sriworawong was put in charge of over viewing a peaceful succession.
Nagamasa, by then another favourite of the king, also was summoned to court, and in view of his eminent position (he had by then 600 to 800 Japanese soldiers under his direct command) he was made to swear fidelity to the dying king and to help in doing whatever necessary to put his son on the throne. In this context, Nagamasa was however subordinated to Phya Sriworawong, who had been chosen by Song Tham to become regent for the young prince, and was de facto the second most powerful man in Siam. This was the beginning of a two-year struggle that ended with dreary consequences not only for Nagamasa, but also for the whole Japanese community in Siam.
Song Tham died on December 12, 1628. His place was taken by his son, who was at the time 15 years old, and an apprentice Buddhist monk. He took the name of King Chetthathirat. As in almost every other succession of the period, the change on the throne was the occasion for some settling of accounts. Phya Sriworawong took the chance to get rid of the people who constituted obstacles on his climb to the throne, and a widespread killing of nobles followed the enthronement of the young king.
Nagamasa clearly disliked such bloodbaths, as proven by an interesting episode described by van Vliet. Two mandarins were taken to one of the city gates where they were to be executed, however, Nagamasa “protected them with his body, embracing both of them thus preventing the blows from raining down on them.” Then, he made sure the mandarins were pardoned.
Soon after Cetthathirat was made king, Phya Sriworawong was promoted to the rank of Chao Phya Kalahom Suryawong.
Resources: “Samurai of Ayutthaya – The Historical Landscape of
Early 17th Century Japan and Siam: Yamada Nagamasa
and the Way to Ayutthaya” by Cesare Polenghi (p. 52-53)
