Ariel Mengarini (1919-1998) was an American chess master, author, and medical doctor (psychiatrist for the Veterans Administration). In 1940 he won the championship of Washington D.C. In 1943 he won the U.S. Amateur chess championship with a perfect 11-0 score. He played in several US chess championships. He took last place in the 1954 US Championship (2 wins, 1 draw, 10 losses). He popularized the opening 1.e4 e5 2.a3, sometimes known as Mengarini’s opening.