This paper discusses spot allocation in the national high school rugby tournament based on a quantitative strength evaluation method. In the national high school rugby tournament in Japan, each prefecture receives one spot except Hokkaido, which has two spots; Tokyo, which also has two; and Osaka, which has three. In this paper, Kanagawa and Fukuoka prefectures, whose representative teams achieved outstanding results in recent nationwide tournaments, are considered good candidates for extra spots in the tournament. This paper proposes an Elo-based quantitative skill evaluation method using about 1,800 match results. The evaluation results show high accuracy (84%) in match result prediction. In addition, the gaps between the winners and the finalists in Kanagawa and Fukuoka prefectures can be estimated. According to the results, the second team in Kanagawa ranked in the top 10 in the nationwide tournament; therefore, Kanagawa should receive an extra spot in it.