Hoon-ko refers to a memorial service which was held around the anniversary of the death of Shinran (1173 - 1262), the founder of Jodo Shinshu (True Pure Land Sect of Buddhism) for the purpose of Hon shatoku (repayment for indebtedness) to the founder.
報恩講とは、浄土真宗の開祖である親鸞(1173～1262)の命日の前後に、宗祖に対する報恩謝徳の為に営まれる法要のこと。