İsmail Zühdi Efendi

His father, Mehmed Kaptan, took him to Istanbul at a young age to learn the Qur'an.

[3] When Mustafa was still quite young, their father took the boy to Istanbul to live with İsmail and study calligraphy with him.

By that time, İsmail had been appointed as an instructor of calligraphy at the Imperial Palace, which is where the young Mustafa Râkim received his formal training, studying under his brother.

[4] The two brothers, İsmail Zühdi and Mustafa Râkim, went on to develop their own style of calligraphy based on the work of Hâfiz Osman.

[4] Mustafa postponed his major calligraphic innovations until İsmail died, in deference to seniority.