Meet Eelke De Boer: The Online Bullet Gladiator
IM Eelke De Boer, known to the Chess.com community as Mackster23, has turned online bullet chess into a blood sport. Though he holds the prestigious International Master title from FIDE, his true kingdom is the 1+0 and 2+1 lanes, where he has played thousands of games and built one of the most recognizable attacking styles on the platform.
From the Lowlands to the Leaderboard
De Boer's online journey began modestly in 2019 with ratings south of 2000, but he climbed with frightening consistency. In 2023 he exploded onto the bullet scene, playing more than 600 games in a single month and crossing 2600. His bullet rating trajectory is a case study in relentless improvement: from 1900 in 2019 to a peak of 2870 (2024-05-02) by May 2024. Along the way he earned his IM title, proving that online blitzkrieg can translate into over-the-board credentials.
A Repertoire Built for Speed
De Boer almost always opens with 1.e4, and his opponents know it. Against the Caro-Kann Defense, he grinds out advantages with trademark patience. He is equally at home facing that same defence as Black, and he routinely takes on the Sicilian Defense: Najdorf Variation in blitz, with hundreds of games in that razor-sharp line. His bullet numbers also show a particular fondness for the Modern, the Alekhine Defense, and even some unorthodox setups like the Nimzo-Larsen Attack. Whatever the opening, he averages more than 80 moves in decisive games, a sign that he plays till the bitter end rather than bailing out early.
Rivalries, Comebacks, and Endgame Grit
No portrait of Mackster23 would be complete without his rivalries. His longest-running feud is against gyg, whom he has faced 118 times. That series has been a war of attrition, with gyg holding the edge while De Boer kept coming back for more. He shows similar stubbornness in his own games: his comeback rate sits at a remarkable 86 percent, meaning he rarely folds after losing a piece. His endgame frequency approaches 85 percent, and his decisive games routinely stretch past move 80. This is a player who scores wins by outlasting opponents rather than by hoping for early blunders.
His most frequent sparring partners also include benecyrl, cockroadolly, and zuraazmai, each played over hundred times. These marathon rivalries speak to a player who thrives on familiar foes, sharp opening prep, and the unique psychology of rematches.
Peak Bullet and Blitz Form
While his title comes from over-the-board play, De Boer's online ceiling is equally impressive. He reached a thunderous peak blitz rating of 2882 (2025-04-27) in April 2025, and his bullet rating touched 2870 (2024-05-02) a year earlier. His best hours are around 7 PM platform time, when his win rate climbs noticeably. He has won 12 games in a row at his peak, and his longest losing streak was 13, a reminder that even elite online warriors bleed rating now and then.