I have previously written about Nichiren Buddhism of which Rissho Kosei Kai shares a common origin with along with the movement known as Reiyukai .
jesusandjews.com/wordpress/2012/06/15/nichiren-buddhism/
It founders Nikkyo Niwano and Myoko Naganuma have incorporated questionable methods of spirituality as being involved in the occultic practices of fortune telling and shamanism. Nikkyo employed fortune telling as a means to gain converts by using peoples names, dates (rokuyo) and directions (shichishin).
Myoko used shamanistic practices and was referred to as a prophetess who occasionally received revelations or messages from the spirit world by means of divination. She also claimed miraculous healing but ironically and tragically her life was plagued with disease and illness which calls to question her position as a spiritual elitist or the belief system regarding karmic forces or both.
My question to you based on the integrity and background of these individuals is why would you place your trust in them as spiritual leaders as being involved in the dark practices of satanic ritual and superstitious behavior?
Anyway on the positive side of this movement is their humanitarian and social achievements nonetheless this is something in which other Japanese people are interested in as well and it doesn’t justify a religious identity or platform to support a philanthropic program. Their ability to be able to behave humanely towards others does not mean that they hold the quintessential key to truth as there are other groups and organizations which are globally doing the same thing.
Originally this movement had its roots in happiness through the elimination of negative karmic forces but latter adopted the perfection of personality and the practice of achieving peace on earth which was a paradigm shift and a reactionary response to several factors such as global conflict, economics and a new generation of believers and thus this move was not primarily inspired by the sacred text of the Lotus Sutra as necessitating truth. So if this group has set its own values and course as based on the emotional tide of cultural changes then what would guarantee that the scenery would stay the same due the shifting landscape of time and how is this centered on a eternal reality due to its temporal scope of activity which might be a short term fix or application of pragmatism?
Anyway based on the position of this organization which allows for interfaith dialogue and participation from other religious backgrounds I would simply ask you to take the opportunity in researching other areas of faith especially if they are already in agreement with the common goal of helping humanity.
In closing I am leaving you with some websites which may be helpful in your quest for spiritual truth.
Encyclopedia of Religion Second Edition, copyright 2005 Thomson Gale a part of The Thomson Corporation, Lindsay Jones Editor in Chief, Vol.11, pgs.7794-7795, Morioka Kiyomi
Encyclopedia of Religion Second Edition, copyright 2005 Thomson Gale a part of The Thomson Corporation, Lindsay Jones Editor in Chief, Vol.8, pgs.5400-5401, James Luther Adams/Thomas Mikelson
Encyclopedia of Religion Second Edition, copyright 2005 Thomson Gale a part of The Thomson Corporation, Lindsay Jones Editor in Chief, Vol.10, pg.6574, Robert S. Ellwood