Event Overview
Emerald Hills Chess, the Tri-Valley Chess League, and the Emerald Knights Chess Club present the Tri-Valley Dec Open, for players of all levels and ages, including youth and adults!
Our low-cost half-day tournaments consistently attract 150+ players (including October's 210-player East Bay Open), from nationally-age-ranked competitors to adult improvers and returnees to after-school chess club members trying out their first tournament!
Flex your chess skills, boost your rating, win one of 50+ trophies and ~$700 in cash prizes, and have fun!
When: Sat Dec. 13 2025, 9-1:30 PM (on-site registrants allowed before 9 AM but not guaranteed 1st round pairing); trophy ceremony start ~1:30 PM
Rounds and Time Control
Championship: 3-round USCF-rated quads with Game in 40 min/5 sec delay
Experts, Premier and Challenger: 4-round rated Swisses with Game in 25 min/5 sec delay
Novices: non-rated 5-round Swiss with 15 minutes and 3 seconds delay per move per player
Sections (based on Dec 2025 published rating - check here)
Championship Quads for USCF/FIDE 1200+ players only
Free entry for 1) All USCF and FIDE titled players (including GMs, WGMs, IMs, WIMs, FMs, WFMs, and NMs) 2) Chess teachers and parent organizers/coaches (any section) bringing students
Prizes: $80 first prize and trophy per quad (split in case of ties); $100 for quads with 1500+ average rating; +/- $20 per additional/fewer player in round-robins (i.e. $100 for 5 players, $120 for 6 players)
Experts for U1200/unrated players of all ages including adults
Prizes: $100 1st place, $50 2nd place. Trophies to Top 5, Top 2 U1000/unrated, and any other Outstanding Performers scoring 3 or more.
Premier for U800/unrated players of all ages including adults
Prizes: Trophies to Top 5, Top 2 U600/unrated, and any other Outstanding Performers scoring 3 or more.
Youth Challenger for K-12 players under 400 rating or unrated
Prizes: Trophies to Top 5, Top 2 U200/unrated, and any other Outstanding Performers scoring 3 or more.
Non-Rated Youth Novices for K-12 players that 1) are unrated, or 2) have provisional (under 25 games) USCF rating under 300; 3) have not won a trophy in a prior Novices tournament.
No USCF membership required.
Prizes: Trophies for Top 5, Top 2 K-2, plus all other Outstanding Performers scoring 3.5 or more.
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Emerald Hills Chess provides professionally-led after-school chess clubs and tournament training classes serving 300+ kids in the Tri-Valley, including our new high-performance (1300+) class led by GM Enrico Sevillano.
Learn more and register now for Spring 2026.
The Tri-Valley Chess League is a student-led non-profit that holds tournaments and classes.
The Emerald Knights Chess Club is a student-led non-profit that holds tournaments and classes.
12995 Harcourt Way
San Ramon, CA 94582
United States