Our Instructors

Tom Crone
Tom Crone
7th Degree Judo Black Belt
Tom Crone began his judo training n 1960 as a freshman at Mankato State College, Mankato, Minnesota. He rose to the rank of shodan (1st degree black belt) in three years, having won successive state championships and placing in the First Collegiate National Championships in Colorado Springs, CO, in 1962.

In 1985, he and Michelle Holtze founded North Star Martial Arts Academy. Since, he has trained at the Kodokan Judo Institute, served five years on the National Junior Olympic Coaching Staff, served Judo Minnesota as its Development Chair for 10 years, one term as President, and in 2002 became its Collegiate Committee Chair. He is a member of its Standards Committee. In 2003 he also became the Midwest Coordinator for the United States Judo Association's Collegiate Committee, and its Chair in 2004.

Crone sensei became the first home-grown Minnesota judoka to reach the ranks of 6th and 7th degree black belt awarded by a nationally accredited judo organization.

He has been the instructor for the University of Minnesota's academic credit course since 1995. He is Sensei Emeritus of North Star Judo.

Mike Norton
Mike Norton
2nd Degree Judo Black Belt

Mike started Judo in 1973 in New York City. His first dojo was in a local school where the mats needed to be set up and taken down for every practice. Mike also frequented other Judo Schools in the area for extra practice with a wider array of judoka. This helped him to hone his skills and place well in local and regional competition. While in New York he also trained at Waseda Judo Club in Baldwin Long Island and Nisei Judo Club in the Bronx.

After leaving New York for Minnesota to accept a position for work Mike found North Star Martial Arts Academy. His judo career continued under the expert training of both Tom Crone and Michelle Holtze. He attained his shodan (1st degree black belt) in 1991. His enjoyment for the sport has taken him as far away as Russia where he and several other United States Judo players spent 14 days training and exchanging ideas and techniques with Russian judoka.

Mike took a brief hiatus to concentrate on raising his two children Frank and Katherine who now also train with him in judo in Burnsville.

Judo has become more than just a fun way to stay in shape and Mike expects to be both teaching and participating in judo for a long time to come. Mike has become head instructor of North Star Judo upon Michelle's death.

Christina O'Brien
Christina O'Brien
3rd Degree Judo Black Belt

Christina O’Brien began Judo in 1987 at age eleven with North Star Martial Arts Academy under the instruction of Tom Crone and Michelle Holtze.  With Tom and Michelle as coach, she placed 1st in the State Championships in 1989 and 1991, received 2nd place in the High School Nationals in 1992 and 1st Place in the Chicago Open in 1990 as well as placing in numerous local tournaments.  She continues to compete as an adult and recently placed 3rd in the 2007 Land O’ Lakes Open, 3rd seniors, and 2nd in masters in the 2008 All Women’s Championships and 1st in masters at the 2011 All Women’s Championships.    Lately Christina has focused on kata competition and has placed at local regional and national events including the 2008, 2009 and 2010 Senior Nationals, and the 2009 Fukuda Invitational.

Christina achieved the rank of 1st degree black belt at age seventeen, making her one of the youngest women in Minnesota to attain this rank.  Prior to teaching Judo at the Burnsville location she had over two years of teaching experience.  She was assistant instructor at a program at Roosevelt High School for one year and also assisted for a time at North Star Martial Arts Academy for Sensei’s Crone and Holtze.

For medical reasons, Christina is no longer teaching judo.

Michelle Holtze
Michelle Holtze
8th Degree Judo Black Belt
Michelle Holtze started judo as a teenager in 1969. She began teaching judo while a student at Mankato State. Upon returning to the Minneapolis are, she eventually took over teaching at her instructor’s school, West Bank Judokan. This evolved into her becoming the co-founder of North Star Martial Arts Academy.

Michelle served as the Standards Committee Chair (Promotion Committee) for Judo Minnesota for several years, and held a variety of other JMI positions.

She and her partner were the first kata competitors to step foot onto the mat for the Pan American Judo Competitions, and won a silver in ju no kata that day in 2000. In the new millennium, Michelle has won numerous national and international kata medals, including the one shown in the photo which is a 1st place for nage no kata at the 2003 World Masters Judo Championships, at the Kodokan in Tokyo.

Michelle was the first Home-grown Minnesota woman to be awarded the rank of 6th dan. She also holds coaching certification with all three accredited national judo organizations. In 2005, she was elected to the Board of Directors of the United States Judo Association. She continues to be the owner and Head Instructor of North Star Judo.

Michelle was born Aug 17th 1954 and passed of natural causes on Aug 3rd 2016. She was promoted honorary 8 Dan upon her death for all she did for the Judo community in the midwest. A memorial was held to bow her off the mat one final time and brought friends and student together to celebrate and share stories. It was truely apparent of her deep involvement and dedication to a sport that she dedicated her life to. She was a true inspiration and amazing instructor.


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