The project of "Christmas City" began in earnest in 2008. In 2006 when Yamaguchi City was certified as the "Birthplace of Christmas in Japan" by the Province of Navarra, Spain, the Chamber of Commerce and Industry and related organizations took the initiative in organizing concerts, Christmas lights, and exhibitions in the shopping arcade and other locations in December. Later on, it developed into a public participatory event with the theme of "Kizuna" between Xavier and Ouchi Yoshitaka.

Meanwhile, some citizens asked if it was possible to hold the opening ceremony at the Xavier Memorial Cathedral. At first, the church was reluctant to hold the ceremony aimed at the general public because of their resistance to having ordinary singers at the altar and fears of attracting an unprincipled audience. Likewise, the government and the Chamber of Commerce took a cautious approach to the church.

In 2012, the church reluctantly allowed citizens to use its hall as a venue, but there was a rift between them. However, the dedication of the civic volunteers, the reverent behavior of the audience, the beautiful voices of the artists, slowly changed the church's view.

In addition, a committee of citizens and church members was established for the ceremony, so that both sides could share their ideas, perspectives, and goals. As a result, the contents of the ceremony were enriched by the church's active involvement such as the songs by the choir and talks by the priest.

Finally, in 2017, "Yamaguchi KOTANSAI Festival" began in the plaza in front of the Cathedral, hosted by local businesses and citizen groups.