Biography
Jacobo Kyushei Tomonaga
About Jacobo Kyushei Tomonaga
Jacobo Kyushei Tomonaga was a Japanese Dominican priest whose work connected Japan, Manila and Taiwan. The Vatican biography places his birth in a Christian family at Kyudetsu and records his education at the Jesuit college in Nagasaki. Expelled from Japan in 1614 while working as a catechist, he continued preaching abroad before returning in 1632.
His work included teaching language as well as religion. Patricia May Bantug Jurilla’s study of early Philippine printing identifies him as Jacobo de Santa Maria, the teacher from whom Jacinto Esquivel learned Japanese in Manila. He also helped Esquivel translate a Portuguese dictionary into Spanish. The resulting Vocabulario de Iapon was printed in Manila in 1630 and was the first Japanese-Spanish dictionary.
That contribution belongs to a collaborative history. The Portuguese material had been compiled by Jesuit missionaries, while Esquivel is credited with the Spanish translation. Tomonaga’s documented role is that of teacher and helper in the translation, rather than sole author. The study connects this language work with preparation for missionary activity in Japan.
His return ended in arrest and death. According to the Vatican account, his catechist Michael Kurobioye disclosed the hiding place under torture, then repented and shared his martyrdom. The account identifies Tomonaga’s religious vocation and propagation of the faith as the reason for his killing.
The papal canonization decree records his death with Michael on August 17, 1633, three days after Dominic Ibáñez and Francis Shoyemon. John Paul II’s later commemoration locates the group’s martyrdoms at Nishizaka in Nagasaki.
Recognition came centuries later. The decree records the group’s beatification in Manila on February 18, 1981, followed by canonization on October 18, 1987. Tomonaga is named individually in the canonization formula, alongside Lorenzo Ruiz and Dominic Ibáñez, with their companions.
The Dominican calendar commemorates him with the group on September 28. His surviving record includes both the final witness of martyrdom and the quieter labor of teaching a language that other missionaries needed to learn.
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