Priest Nichiren, the founder of Nichiren sect Buddhism, came to Kamakura from his hometown in Chiba {chee-bah} Prefecture in 1253 when he was 31 years old and settled here to start missionary work. The Temple claims that Priest Nichiren made a hermitage right on this site, and engaged in various propagation activities over 20 years. Neighboring temples Myohoji and Choshoji also insists respectively that his real hermitage was in their temple precincts. The district is called "Matsuba-ga-yatsu" {mah-tsu-bah-gah-yah-tsu}, and it covers Myohoji district as well. Back in the mid-13th century, Zen sect Buddhism was booming in Kamakura as typically symbolized by the construction of Kenchoji.

Priest Nichiren wrote a famous treatise entitled Pacifying the State by Establishing Orthodoxy in 1260 when he was 39 years old, and presented it to Tokiyori Hojo {toh-key-yoh-re hoe-joe} (1227-1263), who was then in power as the Fifth Hojo Regent. Back at the time, a series of natural disasters and social unrest occurred making people uneasy and scared. In the treatise he addressed that the government should take up the right religion, namely, the Lotus Sutra, and establish the essential truth of Buddhism. Reforming the society through his dogma is the only way, he said, to keep the country secure. The title of this treatise is called Rissho Ankokuron {ris-sho an-kok-ron} in Japanese. Hence the name of Ankokuron-ji. However, the Regent and the Kamakura Shogunate neither agreed to his proposal nor employed his doctrines. Priest Nichiren started his preaching to the people in Kamakura at busy corners of streets in town, bitterly criticizing other sects, which in turn provoked their antipathy toward him, and eventually invited attacks by mob-like Buddhists of the criticized sects. Included among them were Jodo sect Buddhists supported by Shigetoki {she-ghe-toh-key} Hojo (1198-1261), who was a family member of the Hojos and contributed to the construction of Gokurakuji. Faced with the assault by those anti-Nichiren Buddhists in 1260, Priest Nichiren was forced to flee from Kamakura, but returned shortly afterward and continued his campaign undergoing similar persecutions.

As to exactly where Priest Nichiren settled in Kamakura, it has long been an issue disputed by the three temples mentioned above with their close proximity. They even filed suits against the others and argued in the law court. An academic survey, however, concluded that present-day Ankokuronji was the place where Nichiren first settled, and after the first persecution by the mobs, he made another retreat at Myohoji adjacent to Ankokuronji. Choshoji, 200 meters away from Ankokuronji, has nothing to do with his retreat, so revealed the survey.

The current building is rather new, constructed shortly after the Temple was destroyed by the fire in 1961. The main object of worship, the sedentary statue of Nichiren, is fairly new chiseled in 1963. Also placed on the altar are the Odaimoku Tablet, and statues of the following Buddhist deities and priests:

1. Kishimojin {key-she-moh-gin} or the Goddess of Children (Hariti in Sanskrit)
2. Jura-setsunyo {jew-rah seh-tsu-nyo} (raksasa in Skt.): Ten devil-women that appear in the Lotus Sutra. After learning Buddhism, they turned devout believers in the Lotus Sutra and swore to help those who believe in it. Kishimojin and Jura-setsunyo are often venerated by Nichiren sect Buddhists.
3. Daikokuten {dye-kok-ten}: The God of Wealth or the God of Five Cereals (Mahakala in Skt.)
4. Priest Nichiro {nee-che-roe} (1243-1320): One of the Nichiren's six immediate disciples and the second chief priest of the Temple.
5. Shichimen Daimyojin {she-che-men dye-myo-gin}: The guardian deity of Kuonji {koo-on-gee}, the headquarters of all Nichiren sect temples situated in Yamanashi Prefecture.