He participated many times in Argentine championships, and was an Argentine Champion in 1933 winning ARG-ch Torneo Mayor and a match for the title against Jacobo Bolbochán (5.5 : 2.5). In 1934/35, he lost a match to Roberto Grau (5.5 : 7.5), lost a match to Carlos Guimard (2.5 : 7.5) in 1938, and lost a match to Carlos Maderna (6 : 8) in 1940. 
In 1934, he tied for 7-8th in Mar del Plata International Chess Tournament (Aaron Schwartzman won). In 1934/35, he won South American Chess Championship in Buenos Aires. In 1936, he tied for 9-10th in Mar del Plata (it, Isaias Pleci won). In 1944, he took 4th in Buenos Aires (La Regence). In 1952, he won the Club Argentino de Ajedrez Championship in Buenos Aires. In 1959, he took 8th in Quilmes (Alberto Foguelman won).
Piazzini played twice for Argentina in Chess Olympiads:
- In 1937, at first board in 7th Chess Olympiad in Stockholm (+4 –2 =6);
- In 1939, at second board in 8th Chess Olympiad in Buenos Aires (+4 –3 =4).
- Chessville - en Español - Nuestro Círculo #106
- "Major Tournaments and Argentine Chess Championships (notes in Spanish)". Archived from the original on 2009-10-25.
- GER-ch 2nd Aachen 1934 Archived 2010-12-15 at the Wayback Machine.
- Club Argentino de Ajedrez -Más de 100 años de presencia en el Ajedrez Argentino Archived 2008-01-13 at the Wayback Machine.
- Welcome to the Chessmetrics site Archived 2006-04-14 at the Wayback Machine.
- OlimpBase :: the encyclopaedia of team chess