Short answers, pulled from the story.
Shinnyo-en was founded in 1936 by Shinjō Itō and his wife Tomoji Itō in the Tokyo suburb of Tachikawa, where its headquarters remains today. Shinjō was ordained at Sanbō-in temple by Chief Abbot Egen Saeki of the Daigo school of Shingon Buddhism in May 1936.
Shinnyo-en's principal sutras are the Prajnaparamita Sutra, the Lotus Sutra, and the Mahayana Mahaparinirvana Sutra. The central belief, drawn from the Mahaparinirvana Sutra, is that all beings possess Buddha-nature and that nirvana is attainable in the present moment.
Shinsō Itō, born in 1942 as the third daughter of the founders, has led Shinnyo-en since the death of Shinjō Itō on the 19th of July 1989. In 1992 she was conferred the rank of Daisōjō, the highest priestly rank in traditional Shingon Buddhism, by the Daigo-ji monastery.
In Shinnyo-en, sesshin is a roughly three-minute individual guidance session with a specially trained practitioner, aimed at identifying karmic impediments and developing Buddha-nature. This is entirely different from Zen sesshin, which refers to periods of intensive group meditation lasting many hours per day.
The first overseas sanctuary opened in Mililani, Hawaii on the 2nd of March 1971. Subsequent temples were established in Honolulu (1973), San Francisco (1982), Taiwan (1985), France (1985), Los Angeles (1990), Italy (1990), Belgium (1991), Hong Kong (1992), the UK (1994), Germany (1994), Singapore (1994), and Australia (1999).
Shinnyo-en engages in interfaith dialogue, environmental activities, and disaster relief. The organization supports Medecins sans Frontieres, the Red Cross Society, and the World Wildlife Fund, and also operates the Hanzomon Museum in Tokyo.