Third anniversary of death - Ganzanki

Of these, the two in June and November are especially important, and once every five years, in a good season, the two ceremonies are held simultaneously, which is called the Hokke Taikai. Another famous event is the Gensanki, which is held on January 3rd, the anniversary of Ryogen's death, at Shiki-Mido in Yokokawa.
[Temple land]
In 814 (Kōnin 5), Emperor Saga gave Saichō 400 tsubo of regular taxes from Omi Province to use for the construction of the mountain, and in 823 he sent him 400 koku of rice to use for the construction of the eastern and western pagodas.

*Some of the terminology that refers to "Gensanki" is listed below.

Source | Heibonsha World Encyclopedia 2nd Edition | Information

…このうち六月，霜月の両会はとくに重んじられ，5年に1度，好季を選んで両会同時に修し，これを法華大会という。ほかに1月3日，良源の忌日に横川の四季御堂で行う元三忌も有名。
［寺領］
　嵯峨天皇は814年(弘仁5)近江国正税400束を最澄に施して住山の資に，また823年，米400石を送って東西両塔建立の資にあてしめた。…

※「元三忌」について言及している用語解説の一部を掲載しています。

出典｜株式会社平凡社世界大百科事典 第２版について | 情報