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Daniël De Groot

Daniël de Groot links Rotterdam and Santos through teaching, competition and a school that gives beginners a structured start.

Biography

When Daniël de Groot was preparing Haven BJJ, he combined daytime renovation with teaching late into the evening in Utrecht. He described that period to his sponsor Brandzaak: building his own Rotterdam school meant continuing to teach elsewhere while the work was done. As Haven’s founder and head coach, he teaches competition sessions and jiu-jitsu both with and without the gi jacket. His teaching relationships in Rotterdam began much earlier. At six, he attended anti-bullying martial-arts training with Patrick van Daalen. By November 2021 they were colleagues, having founded Checkmat BJJ Rotterdam together. De Groot had taught students at Erasmus Sport since 2015 and at Van Daalen’s Unity99 since 2020. Teaching children was giving him experience he valued while planning a school of his own. Alongside that work, he completed a bachelor’s degree in Public Administration in 2016. Rotterdam School of Management credits him, Teodor Cătăniciu and Erasmus Sport with launching a student BJJ club. Another lasting relationship developed through repeated visits to Santos, Brazil. In his 2023 account, De Groot dated those trips to 2015, when he began training at The House FC under Thiago Abreu and Gabriel Rollo. He described the visits as a way to deepen his technical understanding. The connection also ran in the other direction, with the coaches visiting for seminars and training camps. By March 2019, BJJ Fightgear was presenting him as a full-time jiu-jitsu competitor pursuing the sport after his studies. Its written introduction to his vlog placed teaching alongside training: episode descriptions covered competition classes at The House, afternoon study and further mat time, his own instruction in Brazil, and coaching beginners in Rotterdam. The published series followed him between learning from his Brazilian teachers and taking responsibility for students at home. Competing for CheckMat, he won the adult male purple-belt light-featherweight division at the 2018 Brazilian No-Gi Championship. He added the European No-Gi title in the same age, belt and weight category in 2019. Those results existed alongside difficult trips. In a January 2019 interview with De Havenloods, he looked back on elimination in the second round of the previous month’s no-gi Worlds in Los Angeles. He was disappointed and said it had increased his motivation for the next European event. The same report described his regular Brazilian training and Abreu teaching at Erasmus University, connecting his international preparation to the group he coached in Rotterdam. In November 2021, he was still pursuing ADCC qualification after fourth place at the first European qualifier. He explained grappling’s appeal through the decisions it requires: choosing an action while considering the opponent’s possible responses and how each could change what happens next. His 2022 adult black-belt results included shared third in featherweight at the Brazilian No-Gi Championship. At that year’s European No-Gi Championship he placed second in light feather. He also reached the podium at the second European, Middle East and African ADCC trial in May 2022, finishing third in the professional men’s under-65.9-kilogram division for Checkmat Rotterdam. That event took place near Poznań in Poland; its qualifying places went to professional division winners. At the ADCC Central European Open in June 2023, he won professional adult men’s under-65.9 kilograms, now representing Haven BJJ Rotterdam. The reason for his own school was control of the training space. He told Brandzaak that BJJ too often fitted around other sports’ sessions; he wanted it to take priority. Haven’s offering would include competitive training and a four-lesson introduction, giving newcomers a chance to learn the basics before entering the wider practice. Haven began in February 2023, according to De Groot’s three-year anniversary account published in February 2026. He recalled some early classes having only one or two people. By the anniversary, he described a busy daily schedule, beginners coming through introductory and fundamentals classes, and a growing children’s group. He also named three black-belt graduates from those years: Savage, Bryan and Joffrey. The school’s name joined its two cities. Rotterdam and Santos are both ports; Haven’s own account uses that connection to explain bringing Brazilian jiu-jitsu into Rotterdam. It also uses the word’s sense of shelter to describe a welcoming place to learn. The practical proposal is structured instruction across experience levels, aimed at reducing the uncertainty of entering an unfamiliar training room. No Mercy instructor Dihn Robert describes himself as a blue belt under De Groot in the Rotterdam Haven BJJ/CheckMat setting. He recalls sharing training with accomplished competitors, and says he wants to pass on the confidence the mat gave him. His goal is to help people learn and feel capable even when they have no ambition to become professional fighters. De Groot’s own written introduction for a 2022 BJJNinjas masterclass explains why he keeps competing alongside teaching. He wants competition to test his instruction against strong resistance. His stated standard is to teach techniques he has been able to apply, tying the classroom to problems he has had to solve himself. His Guillotine Revolution course makes that approach concrete through a system rather than a single finishing move. The guillotine is a neck-control submission, but the published curriculum also treats it as a position from which to manage the exchange. It connects standing entries, attacks from top and bottom, finishing variations and responses when a defender counters. The teaching problem is how to retain an attacking route as the situation changes. Footlock Revolution applies a similar organization to lower-body grappling. Its curriculum brings ankle locks and heel hooks together with defenses, entries from guard and transitions between leg entanglements. The positions connecting attacks are part of the subject, alongside the submissions themselves. De Groot also works with Sarah Tuohy. Their public presentation of How to Win in Jiu Jitsu organizes the book around training, environment, strategy, mindset and nutrition. Tuohy is identified as the sports dietitian responsible for the nutrition material and as the coach of Haven’s women’s class. The project places different kinds of expertise alongside De Groot’s competition and coaching experience. Haven’s online-academy presentation likewise outlines a sequence of courses, connected concepts and knowledge questions. It describes an approach for members studying between classes, learners away from Rotterdam and other coaches developing their own lessons. The Brazilian relationship continued as the school developed. Haven’s 2026 account says it followed Abreu and Rollo when they made The House FC an independent team after their years with Checkmat. De Groot had trained and worked under them since 2015. The international team name changed; the school described the teaching relationship and collaboration as continuing.

Sources for this profile

  • Haven BJJ, coach profile.(opens in a new tab)

    • Haven BJJ identifies Daniël de Groot as a black belt.

      Where in the source: Profile table; belt row.

      Accessed:

    • The same Haven BJJ profile gives De Groot’s black-belt degree as one.

      Where in the source: Profile table; belt row.

      Accessed:

    • Haven BJJ lists De Groot’s nationality as Dutch.

      Where in the source: Profile table; nationality row.

      Accessed:

    • De Groot founded Haven BJJ Rotterdam and is its head coach, teaching competition, gi and no-gi classes.

      Where in the source: Biography; classes section.

      Accessed:

  • Haven BJJ, The House affiliation.(opens in a new tab)

    • Haven says De Groot has trained and worked under Thiago Abreu and Gabriel Rollo since 2015, and that the school followed their independent The House FC team in 2026.

      Where in the source: Haven BJJ and The House section.

      Accessed:

  • Haven BJJ, Checkmat account, July 2023.(opens in a new tab)

    • In July 2023, De Groot described repeated training visits to The House FC in Santos under Abreu and Rollo from 2015, with the coaches also visiting for seminars and camps.

      Where in the source: Haven BJJ and Team Checkmat section.

      Accessed:

  • RSM Think.Do., alumni feature, April 2022.(opens in a new tab)

    • Rotterdam School of Management identifies De Groot as a 2016 Public Administration graduate and says he helped Teodor Cătăniciu and Erasmus Sport launch a BJJ student club.

      Where in the source: Teodor Cătăniciu profile; club paragraph.

      Accessed:

  • De Havenloods, De Groot interview, 14 November 2021.(opens in a new tab)

    • In November 2021, De Havenloods traced De Groot’s training with Patrick van Daalen to age six. He taught at Erasmus Sport from 2015 and Unity99 from 2020, co-founded Checkmat BJJ Rotterdam with Van Daalen, and hoped to open his own school. Children’s classes developed his teaching; grappling appealed as planning successive responses. Fourth at the first European ADCC qualifier left his 2022 qualification goal unfinished.

      Where in the source: Main interview; childhood through school ambition.

      Accessed:

  • De Havenloods, Rotterdam competitors, 12 January 2019.(opens in a new tab)

    • In January 2019, De Groot told De Havenloods that his second-round elimination at the previous month’s Los Angeles no-gi Worlds had disappointed him and increased his motivation for the Europeans. The article described his regular Brazilian training and Abreu teaching at Erasmus University.

      Where in the source: De Groot interview between teammate profiles.

      Accessed:

  • BJJ Fightgear, vlog presentation, March 2019.(opens in a new tab)

    • BJJ Fightgear’s March 2019 presentation followed De Groot pursuing full-time jiu-jitsu after his studies, training under Rollo and Abreu in Santos. Its episode descriptions cover competition classes, afternoon study and further training, teaching at The House, and coaching Rotterdam beginners.

      Where in the source: Show introduction; episodes one, five and ten.

      Accessed:

  • IBJJF, Brazilian No-Gi results, 2018.(opens in a new tab)

    • De Groot represented CheckMat when he won the 2018 Brazilian No-Gi Championship’s adult male purple-belt light-featherweight division.

      Where in the source: Adult male purple; light feather podium.

      Accessed:

  • IBJJF, European No-Gi results, 2019.(opens in a new tab)

    • De Groot of CheckMat won adult male purple-belt light feather at the 2019 European No-Gi Championship.

      Where in the source: Adult male purple; light feather podium.

      Accessed:

  • IBJJF, Brazilian No-Gi results, 2022.(opens in a new tab)

    • At the 2022 Brazilian No-Gi Championship, De Groot of CheckMat shared third in adult male black-belt featherweight.

      Where in the source: Adult male black; feather podium.

      Accessed:

  • IBJJF, European No-Gi results, 2022.(opens in a new tab)

    • De Groot of CheckMat placed second in adult male black-belt light feather at the 2022 European No-Gi Championship.

      Where in the source: Adult male black; light feather podium.

      Accessed:

  • MartialMatch, ADCC trial results, May 2022.(opens in a new tab)

    • The second 2022 European, Middle East and African ADCC trial results place Daniel De-Groot of Checkmat Rotterdam third in the professional men’s under-65.9kg division.

      Where in the source: Individual results; first complete division.

      Accessed:

  • MartialMatch, ADCC trial information, 2022.(opens in a new tab)

    • The second European ADCC trial was held near Poznań in Poland on 7 May 2022; its organizer specified that professional division winners qualified for the world championship.

      Where in the source: Event date and venue; prizes section.

      Accessed:

  • MartialMatch, Central European Open results, 2023.(opens in a new tab)

    • Representing Haven BJJ Rotterdam, De Groot won professional adult men’s under-65.9kg at the ADCC Central European Open on 17 June 2023.

      Where in the source: Individual results; first complete division.

      Accessed:

  • Brandzaak, Haven BJJ opening interview.(opens in a new tab)

    • Explaining Haven’s opening to sponsor Brandzaak, De Groot wanted a school where BJJ had priority rather than borrowed mat time. He combined daytime renovation with late teaching in Utrecht and offered a four-lesson introduction for beginners alongside competitive training.

      Where in the source: School-opening interview; motivation, classes and renovation.

      Accessed:

  • Haven BJJ, anniversary account, 2 February 2026.(opens in a new tab)

    • In a February 2026 anniversary account, De Groot dated Haven’s beginnings to three years earlier. He recalled classes of one or two growing into a busy daily schedule, beginners entering through introductory and fundamentals courses, a growing children’s group, and three black-belt graduates: Savage, Bryan and Joffrey.

      Where in the source: Anniversary article; opening through children’s group.

      Accessed:

  • Haven BJJ, school description.(opens in a new tab)

    • Haven explains its name through Rotterdam’s port connection with Santos and the idea of a welcoming place to learn. It describes structured classes across experience levels as its answer to intimidating, unstructured entry into BJJ.

      Where in the source: Why Haven; problem and approach sections.

      Accessed:

  • BJJNinjas, masterclass introduction, November 2022.(opens in a new tab)

    • In his introduction for a 2022 BJJNinjas masterclass, De Groot described competition as a test of what he teaches: he wanted techniques he had applied against strong resistance, rather than relying on untested instruction.

      Where in the source: Daniel de Groot introduction beneath co-instructor biography.

      Accessed:

  • BJJ Fanatics, Guillotine Revolution curriculum.(opens in a new tab)

    • De Groot’s Guillotine Revolution organizes instruction around concepts, finishing variations, standing entries, attacks from above and below, and responses to defenders’ counters. The published curriculum treats the choke as a position as well as a finish.

      Where in the source: Course curriculum; six parts and explanatory prose.

      Accessed:

  • BJJ Fanatics, Footlock Revolution curriculum.(opens in a new tab)

    • Footlock Revolution presents De Groot’s lower-body approach through ankle-lock and heel-hook concepts, defenses, and transitions among straight, crossed and double-leg entanglements, with entries from several guard positions.

      Where in the source: Course curriculum; concepts through final volume.

      Accessed:

  • Haven BJJ, book and author presentation.(opens in a new tab)

    • De Groot and Sarah Tuohy present How to Win in Jiu Jitsu around training, environment, strategy, mindset and nutrition, with Tuohy identified as the sports dietitian responsible for the nutrition material and as Haven’s women’s-class coach.

      Where in the source: Public book landing page; pillars and author profiles.

      Accessed:

  • Haven BJJ, online-academy presentation.(opens in a new tab)

    • Haven’s online-academy page presents De Groot as founder and head coach and outlines sequenced courses, connected concepts and quizzes, intended for members, distant learners and other coaches.

      Where in the source: Academy description; learning pathway and coach sections.

      Accessed:

  • No Mercy Fight Club, instructor account.(opens in a new tab)

    • No Mercy instructor Dihn Robert describes himself as a blue belt under De Groot in Rotterdam’s Haven BJJ/CheckMat setting. He recalls training alongside accomplished competitors and says he wants to pass on the confidence he gained from the mat to people with ordinary, nonprofessional goals.

      Where in the source: Dihn Robert; expanded introduction panel.

      Accessed:

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