Steffen Sontheimer

Steffen Christian Sontheimer was born on 13 September 1990 in Gernsbach, Germany. He studied industrial engineering at the Karlsruhe Institute of Technology before committing to a professional poker career.

Sontheimer began playing online poker under the alias "go0se.core!" on PokerStars, where he achieved Supernova Elite status for two years. He also played as "Partygo0se" on partypoker. His decision to turn pro came in May 2014 during a trip to Canada to play the SCOOP series alongside fellow German players Reiner Kempe, Fedor Holz, and others. His first live cash came in the summer of 2015, and he began competing in high roller tournaments the following year.

2017 was a defining year for Sontheimer. He won the first-ever Poker Masters Purple Jacket, accumulating $2,733,000 in winnings across the series. His victory in Event #5 earned $1,512,000. He also finished fifth in the €111,111 WSOP Europe High Roller for One Drop for €806,758 and cashed in the WSOP Tag Team event. A result in the WPT Bellagio Main Event added $31,506 to his tally.

In November 2018, Sontheimer won the $250,000 Super High Roller Championship at the Caribbean Poker Party, earning a career-best $3,685,000. That same year, he cashed in the WSOP $100,000 High Roller (16th, $155,378) and the WSOP Europe €100,000 King's Super High Roller (15th, €146,907).

Sontheimer has two WSOP final tables and 13 WSOP cashes overall. In 2019, he placed 11th in the $100,000 High Roller ($195,862) and 19th in the $50,000 Final Fifty ($75,483). In 2023, he finished 120th in the $5,000 Six-Handed event for $8,787. His European Poker Tour results include a cash in the 2016 Barcelona Main Event (€9,780), and he placed second in a WSOP Circuit Berlin High Roller in 2016 (€27,745).

Sontheimer is known for an extremely aggressive style, frequently three-betting and four-betting to apply constant pressure. He combines this with solid hand reading, mixing bluffs with value bets effectively. His approach requires excellent bankroll management and emotional control, but can be exploited by adaptable opponents. He has been described as a "crusher" and a formidable opponent in high roller circles.

Online, Sontheimer plays under the screen names "go0se.core!" and "Goon". He is a shareholder in No Limit Gaming, an esports organization founded by Stefan Schillhabel, and streams poker regularly for the team NoLimitGG alongside Fedor Holz. His online presence is marked by the same aggressive style that defines his live play.

Sontheimer resides in Brighton, England, and remains close friends with many top German players, including Fedor Holz and Stefan Schillhabel. He has also mentored other players, helping professional Kitty Kuo improve her game. As of August 2020, he ranked 6th on the German all-time money list; his current live tournament earnings exceed $13.7 million, placing him 8th on the Germany all-time list and 104th globally.

Sontheimer has accumulated over $1.5 million in WSOP earnings from 13 cashes and two final tables. His best WSOP result was a fifth-place finish in the 2017 WSOP Europe €111,111 High Roller for One Drop (€806,758). He also placed 11th in the 2019 $100,000 High Roller ($195,862) and 15th in the 2018 WSOP Europe €100,000 King's Super High Roller (€146,907).

Sontheimer is an active streamer for NoLimitGG, often explaining his thought process during high-stakes sessions. He has mentored players like Kitty Kuo, sharing advanced tournament strategies. His contributions to the poker community extend beyond his own results, as he helps develop the next generation of German poker talent.