Along with his father and his younger brothers Masanori and Masatoki, Masatsura was a supporter of the Southern Imperial Court during Japan's Nanbokucho Wars.
The Court had had little to no resources for three years; the strategy was too focused on defending their base at Yoshino, and not on gaining allies, land, or income.
[3][4] Masatsura tends to be overshadowed by his father, whose tragic story and willingness to sacrifice himself for the Southern Court have inspired many Japanese, from the Edo period to the present day, to see him as a paragon of bravery and loyalty.
Fortuitously happening upon the attempted kidnapping, Masatsura was able to thwart it, and the Southern Court's emperor, Go-Murakami, offered him Ben no Naishi's hand in marriage as a reward.
[6] (Alternative versions of the story recounted in other sources give different reasons, such as his mother's opposition to the match, and there is also a tradition that Ben no Naishi became a Buddhist nun following Masatsura's death.