Meet Our World Class
Masters and Instructors



SABUMNIM Master Herbert

A SaBumNim is a guide and instructor, through whom your martial knowledge of skills will come. To be a SaBumNim means one has earned the honor to pass on the invaluable lessons and experiences of numerous masters and sages. To be a SaBumNim means always being there for one's students and striving to help them achieve their absolute best. To be a SaBumNim means not only having years of martial arts training, but also the ability to produce extraordinary students, Instructors and masters like all those below from individuals just like you.

SaBumNim has been teaching for over 45 years. He is also a certified Zen meditation instructor. He has trained extensively with nine of the world's most renowned, respected and innovative Grandmasters and Masters of the Twentieth Century.These phenomenal martial artists include: Master Chin Yun Chung, Grandmaster Sang B. Ko, Soke John Davis, Grandmaster Jong Yuk Ki, Grandmaster J. Choi, Grandmaster Billy Davis, and Grandmaster Chih-Young Lin. They are all the foundation of Master Herbert's extensive skills,knowledge and understanding of martial arts.


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ChungSaNim Master Dominick Brioche

is a native of Haiti, and a three time Black Belt Hall of Fame inductee,. She holds a 6th degree Black Belt in Jujitsu, a 4th degree in HapKiDo, and a 4th degree in TaeKwonDo. Dominick is the first and only female Shihan in Kumite Ryu Jujitsu under Soke Lil John Davis. Certified as International Instructor in HapKiDo, Dominick has hosted seminars in New York City, Delaware, Washington DC, Haiti and the Dominican Republic. In her constant pursuit of excellence, ChungSaNim is furthering her formal education in Philosophy at the Doctorate level.

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ChungSaNim Master Betty Sze

is a native of NY, and has been training under SaBumNim since 1997. Betty currently holds the rank of 4th Dan in HapKiDo. She has also trained in Wing Chun Kung Fu, Shaolin Kung Fu, Judo, and Jujitsu. Betty holds the rank of 3rd Dan under Soke John Davis in Kumite Ryu Jujitsu. A 3 year stint as a personal trainer and kickboxing instructor, studying directly under a former Mr. America, gave her a solid foundation in the anatomy of the body. Her main goal is to promote martial arts to the world as a way to achieve spirituality, health and empowerment.

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ChungSaNim Master Brad Kagawa

was born and raised in Los Angeles and has been studying martial arts since the age of 10. He practiced several styles, attaining ranks in Tae Kwon Do, Shaolin Kempo, and in Kuk Sool Won before committing to HapKiDo at the WMAC. He currently holds the ranks of 4th Dan in HapKiDo and 2nd Dan in Kumite Ryu Jujitsu. As an instructor, Brad focuses on fundamentals, core concepts and conditioning. He has been teaching children's classes in Brooklyn since 2003. He was proud to see many of his students as part of WMAC's first group of junior black belts.



Master Jill Burdick-Zoll

has trained with Master Herbert since 1998 and has a 4th degree black belt in HapKiDo. She has the rare ability to teach HapKido and martial arts to children as young as 3 and to the elderly. She specializes in joint locking, special weapons and tactics. She graduated from Fashion Institute of Technology with a degree in Fashion Design. She has been a buyer and in product development. She is the USA Sales Manager for Edge Accessories and is married with 2 children.


Advanced Instructor Holly Kozak

was born in Ukraine and immigrated to the US in 1990. She has trained with Master Herbert for over 17 years and is a 3rd degree black belt in HapKiDo. Holly Kozak is a nurse practitioner on the stroke team at Maimonides Medical Center and she teaches graduate students as adjunct faculty at NYU School of Nursing. In addition, Holly is a Licensed Acupuncturist with a degree from Pacific College of Oriental Medicine. Holly has trained many students towards their black belts and continues to teach as an instructor on a regular basis. Holly's focus and emphasis is on quality and precision.


Senior Instructor John Romano

is a native New Yorker born in Brooklyn.   He is a 3rd degree black belt.  John has trained with Sabumnim Herbert for nearly 15 years and has taught and assisted over 500 classes in HapKiDo and Judo.  As a compliment to training at WMAC, John has also trained in other forms of HapKiDo as well as Judo and Kumite Ryu Jujitsu.



Senior Instructor Douglas Graham

is a 2nd dan black belt who has been training in hapkido at WMAC since 2007, and teaching since 2010. Douglas recently retired from a career of teaching and administration within the NYC Department of Education. He believes that individuals learn in many different ways, and that a good instructor adapts his teaching style to the learning style of the student. He believes that a well grounded practice of martial arts is a lifelong learning commitment that helps to keep one physically and mentally fit, which is essential for a safe life in our constantly changing world.


Certified Instructor Jacques-

Philippe Piverger

began studying martial arts when he was 5, and earned his black belt in HapKiDo from Sabumnim David Herbert in 2015. His children are also practitioners of hapkido. Jacques-Philippe has maintained a daily transcendental meditation practice for many years, which he credits for an increasing sense of peace and oneness. He is an entrepreneur having founded or co-founded a number of for profit and for purpose enterprises. He received his undergraduate from Georgetown University and an MBA from Dartmouth. He was a Term Member of the Council on Foreign Relations and he's been designated a Young Global Leader of the World Economic Forum.


ChungSaNim Master Jonathan Waks

received his 1st Dan Black Belt in HapKiDo in 2001, a 2nd Dan in 2004, 3rd Dan in 2010 and 4th in 2015. In addition, he also holds a First Dan – 2008 in VSK Jujitsu - Soke John Davis. Jonathan has over 1500 teaching hours, and has led specialty seminars in weapons, sparring, falling, philosophy, meditation and teacher training. He works as an event and marketing producer in Manhattan.


Advanced Instructor Lena Viddo

is a 3rd Dan black belt in Hapkido at WMAC. She has been a student of Master Herbert for over 22 years. Lena knows how to work with different body types and levels of fitness and can help them build strength, stamina and fluidity, and give them confidence to become amazing martial artists. Lena is an accomplished multimedia artist and painter. Trained in Italy and New York she has been exhibiting internationally and locally for almost three decades. Lena speaks Spanish, Swedish, Italian, French, Portuguese, and English.


Senior Instructor JP McDavid’s

is focused on the holistic method of living and teaching by creating balanced and fulfilling lives. JP was certified in 1994 by the American Aerobic Association International (AAAI) and Full Circle Life Coaching with David-Dorian Ross. JP has accumulated 30 years of teaching experience. He is a 2nd Dan in Han-Su Hapkido, and a senior instructor at WMAC. He is the creator and owner of Enercize, a corporate and individual holistic Wellness Company that promotes Wellness through presentations on the power of choice in our lives.

Senior Instructor
Pete Caban

was born and raised in New York City. He began his training at WMAC with Master Herbert in 2009 and has reached 2nd Dan Hubae. Pete has taught over 3 hundred adult and children's classes, and specializes in sword and dagger. Pete believes that martial arts training improves people's lives and makes them better human beings, and he is devoted to sharing his understanding of HapKiDo with new students.


Certified Instructor Lauren Segal


runs the children’s program, and manages much of the daily operations at WMAC.  Lauren began her training in HapKido in 2012, and has been teaching the children’s classes for several years. She also teaches an adult class on Mondays, which is a high energy, focused 45 minutes.

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Master Eva Vaccaro

was born and raised in Hamburg, Germany. After beginning her training in Hapkido under SaBumNim Herbert, her passion shifted to include the Healing Arts. She holds a 3rd Dan in Hapkido, and   a 1st Degree Black Belt in Kumite Ryu Jujitsu under Soke Lil’ John Davis. Eva has been a Certified Pilates Machine and Mat Instructor, a Certified Fitness Trainer, and is currently certified with AAAI/ISMA. Eva is an herbal practitioner certified by Clayton College of Natural Health.  In 2012 Eva completed her training to become a Holistic Health Coach and is a member of the American Association of Drugless Practitioners.

Senior Instructor Sarah Williams


Senior Instructor
Dr. Rosa J. Cho

has been studying HapKiDo under Master Herbert at WMAC since 2001 and is a 2nd degree black belt.  She has also studied wushu, kickboxing, yoga and swing dancing. Believing in the power of achieving health through empowering one’s mind, body and soul, she brings a lot of positive energy and enthusiasm to every class and cares for each student’s paths to well-being and empowerment. Rosa recently earned a Ph.D from the NYU Silver School of Social Work, and is working on socioeconomic justice and women’s rights issues. 



Certified Instructor Janet Rutkowski

has been training in different martial arts styles for 20 years. She started training in Hapkido at WMAC over a decade ago, and is currently preparing for her 2nd dan black belt. Janet is passionate about teaching children, which she has been doing at WMAC for 7 years. She is loved and cherished by many of our WMAC kids. Janet is an accomplished metal sculptor, and has her work shown in many NYC and upstate galleries.

Certified Instructor Delta Hunter

has been training in HapKido since 2009, and teaching adult classes since 2014. Delta’s classes are high energy, focused on building core strength and learning HapKiDo fundamentals.  Delta is a NYS Licensed holistic psychotherapist with a private practice, a meditation instructor and a portrait photographer.