This volume contains the papers accepted for the special issue on COLIEE 2023, the Tenth Competition on Legal Information Extraction/Entailment, held in conjunction with the 19th International Conference on Artificial Intelligence and Law (ICAIL 2023) in Braga, Portugal, on June 19, 2023. It is a significant highlight that the COLIEE competition has completed a decade of organizing COLIEE, and has helped nurture the development of a world-wide community of research on AI and law. In what began as only a handful of competitors from Japan and Canada, the competition has spread world-wide, and has now had as many as 30 different teams from Africa, Asia, Europe, and North American, including more than 25 different countries.

As in previous years, the overall goal of COLIEE is to formulate a challenging legal informatics competition that engages researchers around the world, and helps build a community that would consider all of computer science and Artificial Intelligence methods to tackle the problems of legal reasoning.

This year there were 19 different teams from 7 countries (China, Canada, Japan, Vietnam, India, United States, Taiwan). This year we received 12 team submissions, with each team providing not only competition test results, but explanations of their performance. Each submission was reviewed by at least 3 program committee members and successful submissions were accepted for publication in the COLIEE 2023 workshop proceedings. In addition, the organizers provided a summary paper for the COLIEE 2023 tasks and solutions, which has been published in the main ICAIL conference. We then solicited a call for papers for the special issue and 7 papers were submitted each of which was reviewed by 3 PC members. Among those submissions, we accepted 6 papers.

We have now completed ten competitions, all of whose selected contributions have been peer-reviewed, published in the ICAIL proceedings or at the Springer Lecture Notes in Artificial Intelligence series, and - most importantly - developed a community of researchers, lawyers, judges, and related communities to discuss the impact and future of technology adoption in for legal systems.

The COLIEE organizers would like to acknowledge the continued support of people and organizations around the planet, including Colin Lachance from Compass Law/Vlex/Jurisage in Canada, who has been particularly support in his work to help develop and extend the case law data for COLIEE, and to Young Yik Rhim of Intellicon in Seoul, who has been our advocate since the beginning of COLIEE. In addition, a number of Japanese colleagues (in addition to the organizing team participants of Ken Satoh, Yoshinobu Kano, and Masaharu Yoshioka) have contributed to the extension and curation of the statute law data for the COLIEE competition.

March 3, 2024.

COLIEE 2023 organizers.