They now hold a coaching qualification level one City and Guilds awarded by Classic Coaching, Chatham, Kent.
The course included lesson planning, coaching adults and children, health and safety and child protection.
All four black belt instructors are members of the Whitby Shotokan Karate Club – they are Sensei Mike Howard, 3rd Dan, Sensei Jim White, 2nd Dan, Sensei Chris Watmouth, 2nd Dan and Sensei Sam Pybus, 1st Dan.
Mr White said the origin of the art of karate was for self defence – and nothing is more obvious today than the need to defend yourself.
"We all hope we will never be called upon to use the skills which we train in," he said.
"Unfortunately in these unsettled times it is more likely you will find yourself in a violent situation at some point in your life.
"This could be when out walking, a night out on the town or even in your own home by an intruder.
"Most of these situations occur when you least expect it and mostly when you cannot call for assistance.
"A solid knowledge of karate will allow you to defend yourself and others."
Mr White said training in karate will improve people's stamina, strength and physical fitness.
"The energetic exercises and power development used in karate will surprise you at first and the stances will make your arms and legs feel tired," he said, "but in time your body will become accustomed to it and you will feel much better in the long run.
"Many people especially children study karate in order to build up their self-esteem and self-confidence.
Students get the satisfaction of achieving promotion as they work their way through the belts and the final accomplishment on attaining the converted Black Belt.
Whitby Shotokan Karate Club members train twice weekly at Airy Hill Primary School courtesy of headmaster Jim Lidgley.
The club is a members of the Independent Federation Of Martial Arts.
All instructors are qualified black belt Senseis and registered with the federation.
Its training times are as follows, Monday and Thursday, novices 5.30pm to 6.30pm with the intermediates 6.30-7.30pm and advanced 7.30-9pm.
For further information call Mike Howard on (01947) 604861 or Jim White (01947) 820378. You can email jwhite16@mypostoffice.co.uk