In the early ninth century, Jang supported Ennin both physically and mentally for his one-and-a-half-year pilgrimage in search of law by donating the Chisan Fahua Temple in the port city of Chisan in the Shandong Peninsula (where many Silla merchants were residing), saving Ennin from an unlawful overstay in Tang when he was only allowed to stay there for a short while (by negotiating with a local officer to have his Kugen [visitor permit] granted when Ennin decided to overstay).
9世紀前半、山東半島の港町・赤山（当時多くの新羅商人が居留するところとなっていた）に赤山法華経院を寄進するとともに、短期で帰国しなければならなかった入唐請益僧円仁の長期不法在唐を実現（不法在留を決意した円仁のために地方役人と交渉して公験（旅行許可証）下付を取り付ける）したのを始め、円仁の9年6ヶ月の求法の旅を物心両面にわたって支援した。