Mark Diesen (born September 16, 1957 in Buffalo, New York, died December 9, 2008 in Conroe, Texas) earned the International Master title in 1976 by winning the World Junior Championship ahead of such noted players as Lubomir Ftacnik and and Oleg Romanishin. He was also the Louisiana State Champion in 1986, 1987 and 1988.
His father, Carl Diesen, was a strong tournament chess player in the mid-1940s, which resulted in strong family support for Mark's chess career. Diesen was a student of Grandmaster Lubosh Kavalek who, at the time, was one of the top rated GM’s in the world. Diesen was a player with a positional style that made him a difficult opponent to face for even the most experienced IMs and GMs. Among the top players he defeated in his short career were Larry Evans, Borislav Ivkov, John Nunn and Eugenio Torre.
Diesen’s only appearance in the US Championship was in 1980 but he had to withdraw after three rounds. He was well on his way to becoming Grandmaster when, in 1980 he began having drug problems. To his credit he overcame the problem and completed his college education. He was to return to chess off and on, but never seriously.
A graduate of the University of Tennessee, he had a degree in Chemical Engineering and after abandoning chess he worked as a reservoir engineer for Shell Oil, Pennzoil and Noble Energy. He was married with three daughters.
Here is his obituary from a Knoxville, TN, newspaper:Mark Carl Diesen - age 51 of Conroe, Texas native of Buffalo New York, passed away suddenly December 9, 2008 in Conroe, Texas. He was a graduate of the University of Tennessee with a degree in Chemical Engineering. He worked as a reservoir engineer for Shell Oil, Pennzoil and Noble Energy. Mark was a World Junior Chess Champion in 1976, the US Junior Co-Champion, the Louisiana State Champion in 1986, 1987, 1988, Texas State Champion, Southwestern Open Champion, and an active chess coach in Houston, Texas and online. He is survived by his wife, Melinda Diesen of Conroe, Texas; daughters and sons-in-law, Gina and Travis Perkins of Knoxville, Amy and Daniel Smith of Houston, TX, and Sarah Diesen of Conroe, TX; mother, Marjorie Diesen; sister and brother-in-law, Laura and J.C Butler all of Bristow, VA; father-in-law and mother-in-law, Paul and Joyce McGlothin of Knoxville; brother-in-law and sister-in-law, Paul and Meredith Averill-McGlothin of Ossining, NY; several nieces and nephews. Funeral service will be 1:00 P.M. Saturday at The Episcopal Church of the Ascension with Rev. Dr. Howard J. Hess officiating. Interment to follow at Highland Memorial Cemetery. In lieu of flowers, memorials may be made to the U.S. Chess Trust, PO Box 838, Wallkill, NY 12589, 800-388-5464. Friends may call at their convenience at Rose Mortuary Mann Heritage Chapel. www.rosemortuary.com
Here is one of his games against IM Julio Kaplan: