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Steffen Sontheimer, known in the digital realm as “go0se.core!,” is a German professional poker player and one of the most respected technical minds in the high-stakes community. A trailblazer of the modern “solver” era, Sontheimer rose to global stardom by capturing the inaugural Poker Masters Purple Jacket and has since established himself as an elite coach and high-stakes cash game specialist.
Career Earnings & Biggest Results
With total live tournament earnings surpassing $13,739,000 (according to The Hendon Mob), Sontheimer ranks #8 on Germany’s ultra-competitive All-Time Money List. His career-best live score of $3,685,000 came from his victory in the 2018 Caribbean Poker Party $250,000 Super High Roller Championships. Sontheimer’s most iconic achievement remains his dominant performance in the 2017 Poker Masters, where he cashed in four out of five events and won two, earning $2,733,000 and the first-ever Purple Jacket. While he has focused more on high-stakes cash games in recent years, his massive tournament results and online dominance contribute to an estimated poker net worth of over $14 million.
Biography & Poker Background
Born in 1990 in Germany and currently residing in Brighton, England, Sontheimer’s journey began in the high-stakes online cash game arena. Under the handle “go0se.core!,” he became a legendary figure on PokerStars, known for his relentless work ethic and analytical precision. He burst onto the live tournament scene in 2015, quickly joining the elite group of German “crushers” that included Fedor Holz and Rainer Kempe. Unlike many who chase tournament glory, Sontheimer has always maintained that he is a “cash game player at heart.” In 2020, he transitioned into a mentorship role, joining Pokercode as a lead cash game coach alongside Fedor Holz and Matthias Eibinger. Today, he is widely regarded as one of the best teachers in the game, balancing private coaching with occasional appearances in the world’s most prestigious high-roller events.
Play Style & Strategy
Sontheimer is renowned for a “purely GTO-based and clinical” play style. He was one of the earliest adopters of advanced solver technology, using it to develop a strategy that is theoretically unexploitable. His approach is characterized by extreme technical balance and a “no-ego” mindset, famously stating that he retired from full-time tournament travel because the games had become “too solved” to maintain the massive edges of the past. He is a specialist in deep-stacked No-Limit Hold’em, where his ability to navigate complex turn and river scenarios exceeds almost any other player on the circuit. As a coach, he emphasizes “logic over memorization,” teaching students how to understand the underlying mechanics of poker software. Whether navigating a World Series of Poker (WSOP) high roller or a $200/$400 online cash session, his strategy revolves around technical perfection and emotional stoicism.
Social Media & Online Presence
Want to follow “The Goose” as he coaches the next generation and occasionally crushes the high-stakes circuit? You can find him here:
Video Highlights:
Watch Steffen Sontheimer break down his thought process during a high-stakes $5,000 online cash game session:
