Simon Elgersma: The Iron Grinder of Online Blitz
Introduction
Simon Elgersma, widely known by his username Simoncelli15, is a FIDE Candidate Master who has built a reputation as one of the most active and durable online chess competitors. His preferred battleground is Blitz, where he has played thousands of games and reached a peak rating of 2514 (2024-12-21). There is perhaps no better proof of his longevity than his rating chart, which shows a steady climb from 2016 through 2026.
Early Years and Rise
Simon first appeared in online records in August 2016 with a humble 1383 Blitz rating, and within a month he had already broken past 2000. His ascent was rapid, and by the end of 2017 he was a fixture in the 2100 to 2200 range. The real explosion came in 2019, when he played more than 2,000 Blitz games in a single year and pushed his rating deep into the 2300s.
His climb was not a straight line. He would often surge to a new high, only to slip back and then climb again. By late 2024 he touched a 2514 (2024-12-21) of 2514, a milestone that reflects his ability to maintain high level form over a long period. For a player who started just below 1400, that journey represents one of the most persistent grinds in online chess.
Playing Style and Opening Repertoire
Simon's opening choices are as interesting as his marathon sessions. With Black he leans heavily on the Caro-Kann Defense, playing it in over 800 Blitz games and scoring at a solid 50 percent. He also enjoys the French Defense, where his win rate climbs to nearly 53 percent, and he has a surprising fondness for offbeat lines like the Amar Gambit, which he plays with both colors.
With White he frequently opens with the English Opening and the Nimzo-Larsen Attack, and his stats in the English Opening are particularly strong. This mix of classical foundations and unorthodox experiments makes him a difficult player to prepare against. His opening diversity is visible in his performance chart.
Resilience and Habits
Simon is not a quick resigner. His early resignation rate is just over 1 percent, and his average winning game lasts about 74 moves, suggesting a patient grinder who enjoys converting small advantages in the endgame. His endgame frequency is over 74 percent, and his comeback rate is a staggering 86 percent, meaning he rarely gives up even when the position looks lost.
Online chess can be a psychological roller coaster, and Simon has felt both extremes. He has enjoyed a 15 game winning streak but also endured a 10 game losing streak. He is also an early bird, with his best results coming in the early morning hours, when his win rate climbs to nearly 77 percent. When he delivers the first check, his win rate jumps to 61 percent, a sign that he understands the value of seizing the initiative.
Famous Rivalries
No biography of Simon would be complete without mentioning his extraordinary rivalry with Nick Maatman. The two have faced each other 397 times in Blitz, with babbelbox holding the edge, but Simon's 103 wins show that he never stops fighting. Another frequent opponent is Onno Elgersma, a 44 game series that is almost perfectly balanced at 21 wins each.
Against rubiesch, however, Simon dominates with 35 wins against only 5 losses, showing that he can be a nightmare matchup for certain players. These rivalries, built over years of daily battles, give his online career a personal and competitive texture that pure ratings cannot capture.
Legacy
Simon Elgersma may be best described as a volume virtuoso. With thousands of games under his belt, he has turned the online Blitz arena into his personal laboratory, testing the Caro-Kann Defense, the French Defense, and everything in between. His Candidate Master title is well earned.
Whether he is grinding out a 70 move endgame or launching a gambit attack, Simoncelli15 remains one of the most entertaining and resilient figures in online chess.