Sokyu initially conducted business of selling leather goods such as deerskin (to be used in producing armor, for instance), which were demanded munitions around that time, thereby not only making a fortune but giving him more opportunities to strengthen ties with Sengoku daimyo (Japanese territorial lords in the Sengoku period) in many provinces.
初めは当時軍需品としての需要があった鹿皮などの皮製品（甲冑製造などに用いる）の販売を扱っており、それによって財をなしたのみならず、各地の戦国大名とのつながりを深めていくきっかけとなった。