His baptismal name was John, and he was born on 22 August 1836, the second son of Dimitri Ivanovich Kasatkin, who was a deacon at the church of Beryoza in the Smolensk province. He studied theology at the St Petersburg theological academy
He was appointed as chaplain at the Russian consulate in Hakodate. He crossed Siberia by coach in July 1860, and reached Nikolaevsk at the end of September. He stayed there for the winter, where he met the famous Siberian and Alaskan missionary, St Innocent of Alaska (Veniaminov). He continued his journey in the following year, and reached Hakodate in July 1861
At that time Japan was very xenophobic, and evangelism was very difficult. He studied Japanese language, history and culture, and also gave Russian lessons to Japanese people who were interested.
A samurai landowner and Shinto priest, Takuma Sawabe, regarded Fr Nikolai as a threat to Japan and its culture, and went to the consulate where he threatened to kill him if he did not stop telling people about the Christian faith. Nikolai's reply was to ask if he knew what he was teaching. Sawabe said he did not, and Nikolai asked if it was reasonable for him to kill someone for teaching something he did not know, and whether it would not be more reasonable to hear what he was teaching first. Sawabe agreed to hear, and was convinced of the truth of the Orthodox Christian faith.
Feast Day - February 3rd
Troparion (Tone 4)
O holy Saint Nicholas, the Enlightener of Japan,
you share the dignity and the throne of the Apostles:
you are a wise and faithful servant of Christ,
a temple chosen by the Divine Spirit,
a vessel overflowing with the love of Christ.
O hierarch equal to the Apostles,
pray to the life-creating Trinity,
for all your flock and for the whole world.