1938-1959
| 1938 | March 5 | Founder Nikkyo Niwano and Cofounder Myoko Naganuma establish Rissho Kosei-kai with approximately thirty members. |
| 1942 | May | Construction of Rissho Kosei-kai’s first training hall is completed in Tokyo. |
| 1945 | November 15 | Rissho Kosei-kai enshrines the Eternal Buddha Shakyamuni, Great Benevolent Teacher, World-Honored One as its focus of devotion. |
| 1951 | October | The Federation of New Religious Organizations of Japan is established. Rissho Kosei-kai joins the federation and promotes interreligious dialogue and cooperation in Japan. |
| 1957 | September 10 | Cofounder Myoko Naganuma passes away at the age of sixty-seven. |
| 1958 | June–August | Founder Niwano makes his first official visit abroad, interacting with local members in Brazil and the United States. |
| 1959 | March | Rissho Kosei-kai forms its first overseas chapter in Hawaii. |
1960-1979
| 1962 | June | Rissho Kosei-kai proclaims its “Members’ Vow,” which concisely expresses the essence of the faith. |
| 1964 | May | Construction of the Great Sacred Hall, the main training center, is completed in Tokyo. |
| 1965 | September | Founder Niwano attends the opening ceremony of the fourth session of the Second Vatican Council and has an audience with His Holiness Pope Paul Ⅵ, which inspires the Founder to promote interreligious dialogue and cooperation worldwide. |
| 1966 | Rissho Kosei-kai of Hawaii is established. | |
| 1968 | January | Founder Niwano attends a Kyoto peace conference of Japanese and U.S. religious leaders, an initial step toward the creation of a world interreligious conference for peace. |
| 1969 | July | Rissho Kosei-kai joins the International Association for Religious Freedom (IARF). |
| 1970 | October | Religions for Peace (RfP) is established as an international interreligious organization. Rissho Kosei-kai attends the First World Assembly of RfP, held in Kyoto, Japan. |
| 1971 | Rissho Kosei-kai of San Francisco is established. | |
| 1971 | Rissho Kosei-kai of Seattle is established. | |
| 1972 | Rissho Kosei-kai of Los Angeles is established. | |
| 1974 | August | Rissho Kosei-kai attends the Second World Assembly of RfP, held in Leuven, Belgium. |
| 1975 | The Donate-a-Meal Movement and the Donate-a-Meal Fund for Peace are launched. | |
| 1975 | April | In cooperation with local people, youth members of Rissho Kosei-kai build the Friendship Tower in Bataan, Philippines, as a memorial to those who lost their lives in World War II and as a symbol of reconciliation and enduring friendship between the Philippines and Japan. |
| 1975 | Rissho Kosei-kai of Brazil is established. | |
| 1977 | April | Rissho Kosei-kai begins providing food, clothing, and temporary accommodation at its Dharma centers to Vietnamese refugees who fled the country by sea following the end of the Vietnam War. |
| 1977 | Rissho Kosei-kai of Chicago is established. | |
| 1978 | June | As a representative of RfP, Founder Niwano makes a speech at the first Special Session of the UN General Assembly Devoted to Disarmament. He appeals to the world’s politicians, saying, “Instead of taking risks with arms, please take major risks for peace and disarmament.” |
| 1979 | May | Rissho Kosei-kai cooperates with the United Nations International Children’s Emergency Fund (UNICEF) and starts a UNICEF fund-raising campaign. |
| 1979 | August | Rissho Kosei-kai attends the Third World Assembly of RfP in Princeton, New Jersey, in the United States. |
1980-1999
| 1980 | June | Founder Niwano visits Iran, asking for resolution of the Iran hostage crisis that had occurred the previous year. |
| 1980 | Rissho Kosei-kai of New York is established. | |
| 1982 | May | Rissho Kosei-kai members collect signatures in a campaign for disarmament and nuclear weapons abolition launched by the Federation of New Religious Organizations of Japan. |
| 1982 | June | As a representative of IARF, Founder Niwano makes a speech at the second Special Session of the UN General Assembly Devoted to Disarmament. |
| 1983 | April | The First Niwano Peace Prize is awarded to Archbishop Helder P. Camara. |
| 1984 | July | The Twenty-Fifth World Assembly of the IARF meets at Rissho Kosei-kai headquarters. |
| 1984 | August | Rissho Kosei-kai attends the Fourth World Assembly of RfP, held in Nairobi, Kenya. |
| 1984 | December | Responding to a severe African drought, Rissho Kosei-kai participates in the Campaign for Sharing Blankets with People in Africa, a united effort of the government and ordinary citizens. |
| 1986 | October | Rev. Nichiko Niwano, then the President-designate, attends a World Day of Prayer for Peace held in Assisi, Italy, under the auspices of the Vatican. |
| 1988 | June 8 | As president of Rissho Kosei-kai, Founder Niwano makes a speech at the third Special Session of the UN General Assembly Devoted to Disarmament. |
| 1989 | January | Rissho Kosei-kai attends the Fifth World Assembly of RfP, held in Melbourne, Australia. |
| 1991 | October | Members of Rissho Kosei-kai from around the world assemble in Tokyo for the First World Sangha Assembly. |
| 1991 | November 15 | In a ceremony for the inheritance of the lamp of the Dharma, Rev. Nichiko Niwano is inaugurated as the second president of Rissho Kosei-kai. |
| 1992 | Rissho Kosei-kai of Hong Kong is established. | |
| 1994 | January | Rissho Kosei-kai joins Japan Emergency NGO, an organization formed to provide emergency relief in the former Yugoslavia, and begins participating in its Little Bags of Dreams Campaign. |
| 1994 | July | Rissho Kosei-kai holds its first annual International Lotus Sutra Seminar, in which researchers discuss themes related to the Lotus Sutra. |
| 1994 | November | Rissho Kosei-kai attends the Sixth World Assembly of RfP, held at Riva del Garda, Italy. |
| 1994 | Rissho Kosei-kai of Bangkok is established. | |
| 1994 | Rissho Kosei-kai of Kathmandu is established. | |
| 1995 | April | Members of Rissho Kosei-kai from around the world assemble in Tokyo for the Second World Sangha Assembly. |
| 1995 | Rissho Kosei-kai of San Antonio is established. | |
| 1996 | Rissho Kosei-kai of Oklahoma is established. | |
| 1997 | Rissho Kosei-kai of Korea is established. | |
| 1998 | March | Rissho Kosei-kai sets its general goal as “Cultivating the fields in the hearts and minds of each and every person.” |
| 1998 | Rissho Kosei-kai of the UK is established. | |
| 1999 | October 4 | Founder Niwano passes away at the age of ninety-two. |
| 1999 | November | Rissho Kosei-kai attends the Seventh World Assembly of RfP, held in Amman, Jordan. |
| 1999 | Rissho Kosei-kai of Tainan is established. |
2000-2019
| 2000 | December | International Buddhist Congregation of Rissho Kosei-kai is established. |
| 2000 | Rissho Kosei-kai of Taipei is established. | |
| 2002 | June | Four Sri Lankan Theravadin prelates make “The Tokyo Statement,” a joint declaration for peace supported by Rissho Kosei-kai. |
| 2003 | February–April | Rissho Kosei-kai appeals to the Japanese government to resolve the Iraq War peacefully and begins a fund-raising campaign to support the restoration of Iraq. |
| 2006 | August | Rissho Kosei-kai attends the Eighth World Assembly of RfP, held in Kyoto, Japan. |
| 2006 | October | Members of Rissho Kosei-kai from around the world assemble in Tokyo for the Third World Sangha Assembly. |
| 2006 | December | Rissho Kosei-kai International is established as a division of the organization that will specialize in disseminating the faith internationally. |
| 2007 | December | Rissho Kosei-kai International of North America and Rissho Kosei-kai International of South Asia are established. |
| 2008 | July | President Niwano attends the World Conference on Dialogue under the auspices of the Muslim World League. |
| 2009 | Rissho Kosei-kai of Ulaanbaatar is established. | |
| 2010 | Rissho Kosei-kai of Bangladesh is established. | |
| 2011 | March | The Great East Japan Earthquake occurs, causing a large tsunami and great loss of life and property; Rissho Kosei-kai participates in relief activities. |
| 2011 | Rissho Kosei-kai of Kolkata is established. | |
| 2011 | Rissho Kosei-kai of Sakhalin is established. | |
| 2012 | Rissho Kosei-kai of Rome is established. | |
| 2012 | Rissho Kosei-kai of Sri Lanka is established. | |
| 2013 | November | Rissho Kosei-kai attends the Ninth World Assembly of RfP, held in Vienna, Austria. |
| 2015 | Rissho Kosei-kai of Bodhgaya is established. | |
| 2016 | May | Members of Rissho Kosei-kai from around the world assemble in Tokyo for the Fourth World Sangha Assembly. |
| 2018 | May | In Yangon, Myanmar, President Niwano takes part in a gathering of religious leaders who support peace in Myanmar. |
| 2019 | August | Rissho Kosei-kai attends the Tenth World Assembly of RfP, held at Lindau, Germany. |
2020-Present
| 2020 | April | In response to the global spread of COVID-19, Religions for Peace International holds an online prayer gathering titled “An Interfaith Moment of Hope and Solidarity.” President-designate Kosho Niwano offers words of prayer from the Great Sacred Hall. |
| 2022 | March | In response to the escalating conflict in Ukraine, Rissho Kosei-kai holds a worldwide recitation of the Threefold Lotus Sutra to pray for peace in Ukraine and honor the victims. |
| 2024 | April | As part of the children-led Donate-a-Meal Movement, the “Dream Gift” initiative is launched. Nearly 1.9 million yen and more than 1,300 heartfelt letters have been contributed for children affected by the ongoing conflict in Ukraine. |
| 2026 | April | In response to military attacks on Iran by the United States and Israel, Rissho Kosei-kai holds a worldwide recitation of the Threefold Lotus Sutra to pray for an end to armed conflict in the Middle East and honor the victims of all wars and conflicts. |