Guardian Gym employs a number of the leading instructors in the Bay Area, all of whom have taught and competed professionally in boxing, jiu jitsu, kickboxing, judo and other martial arts at highest levels, including the UFC and the Olympics. They are experts at teaching students from all levels - from total newbie to those preparing for a professional fight - and are excited to have you join our gym!

In addition to being excellent teachers, our instructors strive to be leaders and role models for our youth students and in our local community. Out team is an incredible group of people, in every sense.

In addition to our normal classes, our instructors offer private individual classes to help students rapidly improve their skillset, as well as corporate classes for organizations looking to host team building events, and special seminars for hosting teachers from other gyms.

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Caleb Khan - Head Brazilian Jiu Jitsu Instructor

Caleb grew up in the East Bay and wrestled at Albany High School. Soon after graduating, he began training Brazilian Jiu Jitsu at Ralph Gracie Berkeley under the tutelage of Dave Clahan (one of Ralph's first black belts) and Professor Eduardo Fraga. Caleb received his black belt in 2015, and has competed in numerous BJJ competitions around the country. Caleb's fascination with health and the human body inspired him to major in Kinesiology in college at the University of San Francisco. Everyone practicing jiu jitsu at Guardian is extremely lucky to have Caleb's expertise as they continue on their martial arts journey.

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Bilal Mahasin - Boxing Instructor

Bilal is the current Jr. Welterweight GBO champion. He is also a youth mentor, motivational speaker, and coach of our amateur boxing team. Bilal grew up in Oakland, California, and started boxing at the age of 15. He views the sport as a "savior", seeing it is a powerful tool which can help heal struggling communities. He believes that everything you learn inside the ring can be used outside of it in everyday life.

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Ben Kovacs - Founder

Ben has been practicing jiu jitsu and boxing for 11 years, starting at the Yamasaki academy in Washington DC under the watchful eye of Fernando Yamasaki. After venturing west, he joined the Ralph Gracie academy.  Beyond the obvious benefits in self-defense and self-confidence, Ben has always loved the community provided by martial arts academies. He believes that these sports can transform a person’s life in a variety of ways, promoting mental health and producing measurable benefits at home, work, and school. This inspired him to launch the Guardian Project, as he hopes to give the gift of martial arts to as many as possible throughout the rest of his life.      

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Sacha Feinmann - Managing Director

Sacha first stumbled into Renzo Gracie's New York City jiujitsu academy in 2007, and it changed everything. Martial arts quickly became his abiding passion, around which he planned his days and designed his life. He has trained in gyms all over the country, picking up experience in boxing and MMA along the way, and has come to see combat gyms as incredible venues for building communities and helping people. Before coming to work at Guardian, he spent 10 years as investigative journalist and collected a couple of degrees, none of which are half as interesting or important as the time he has spent on the mats, teaching and learning.

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Eric Watkins - Co-Head Boxing Coach

A Golden Glove Champion with almost 20 years of boxing and martial arts experience, Coach Eric learned first hand the rewards that come from the neighborhood boxing gym.   Remembering the unity built as an amateur, he wanted to give back to the next generation of boxers.   Originally from Cleveland, he began coaching at risk youth in the bay area after moving west.   A strong advocate for boxing being accessible to everyone, he fights for all walks of life to have the opportunity to realize the benefits that come from training in the sweet science.


Mollii Khangsengsing - Brazilian Jiu Jitsu

Mollii is a black belt in Brazilian jiu-jitsu under 9x World Champion Leticia Ribeiro with 11 years of experience. She is the founder of the Sweaty Betties, one of the first open mats in the country to offer free, weekly training to women. In 2010, she organized one of the largest women’s grappling camps in the country featuring several World Champion instructors, drawing attendees from all over the world. Since then, Mollii has run camps in the San Francisco Bay Area, Los Angeles, Maui and Costa Rica. She is also a TRX and Ginastica Natural certified personal trainer. In addition to jiu-jitsu, she has several years of experience teaching self-defense, Ginastica Natural,Tabata, bootcamp and circuit training. As a lifelong athlete, Mollii understands how sports and physical activity can change one’s life for the better. She first immigrated to the U.S. as a young child, and it was through her love of sports that she was able to quickly adapt to a new country and language. When Mollii isn’t teaching or training, you can find her slurping on a giant bowl of ramen noodles or climbing up the nearest coconut tree.

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Tyson Griffin - MMA and No Gi Jiu Jitsu

Tyson is a seasoned MMA fighter who rose up through the ranks in the bay area before making a name for himself in the UFC. He was a standout wrestler at Albany High School. After graduation, he discovered the world of MMA and never looked back. During his career in the UFC, he was awarded 5 fight of the night bonuses, defeating former 155 lb champion Rafael Dos Anjos in the process. As a youth, Tyson found relief from the pressures of life in the course of training in wrestling and MMA, and wants to give back to the young adults that need it most today. He has a passion for teaching functional martial arts that are effective, and his classes combine no-gi jiu jitsu, kickboxing, western boxing, as well as wrestling.  

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Josuke Tanaka - Brazilian Jiu Jitsu and Judo

Josuke has been training in martial arts for over 20 years. Born and raised in Switzerland, he is a black belt in both Judo and Brazilian JiuJitsu. He moved to Japan after High School in order to focus on Judo competition, eventually becoming the 2X Swiss National Judo Champion. After obtaining a Masters Degree in Biomechanical Engineering, Josuke became a Doctor of Chiropractic with a post-Doctorate in Neurology. When he isn't training or teaching, Josuke is working at his clinic where he focuses on the treatment of sports injuries, brain trauma and the care of children with leaning disabilities and behavioral issues.

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Ramon Matthews - Co-Head Boxing Coach

Ramon caught the boxing bug as a child growing up in Baltimore. He learned from the best amateurs and professionals around before relocating for warmer climates in the Bay Area. He first began coaching amateur fighters in 2012, soon moving on to work with professional boxers and MMA fighters. With so much to teach, it was only natural that Ramon next began leading classes and mentoring youth communities. He's a friendly, approachable person, and is always happy to answer any question!


Vince Vasquez - Kickboxing

Vince is a Bay Area native and has been training in martial arts since 1993.  He began his training in traditional striking arts and earned a black belt in Tae Kwon Do before starting kickboxing. Vince fell in love with San Shou Kickboxing (also called Sanda) after meeting Brent Hamby, US National San Shou Champion and head coach of the Oakland San Shou Team. 

Vince's approach to teaching is step by step. He breaks down the movements so you can be effective and efficient when it counts the most. He's passionate about helping his students bring out their best through training.

Vince continues to train in traditional disciplines including, Northern Shaolin, Tai Chi and Japanese sword. 


 Alex Nichols - Kinstretch

Alex grew up spending much of his time in the Bay Area and East Coast Canada (the Canadian roots is what makes him so charming). He is passionate about coaching human movement from the rehabilitative stages through high-level performance. As a coach and as a martial artist, his biggest motivation is to be on the front line of experts teaching students how to improve methodologies for training and recovery. 

He studied Psychology and Philosophy as an undergrad, and is looking to pursue graduate studies in Physical Therapy. Alex is a Ralph Gracie Jiu Jitsu Purple Belt and Judo Brown Belt. He holds a certification as a Functional Range Conditioning Mobility Specialist, is a Certified Functional Strength Coach under Mike Boyle, and a licensed Kinstretch Instructor.