In the world of diving, there are many schools, courses and various kinds of equipment. This is because the underwater world is unimaginably diverse and multifaceted.

   I am sure experienced divers will also learn something interesting. I will consider not so much the training systems as the skills offered on the course. Ultimately, it is the instructor who is the role model and plays a crucial role in teaching students what he knows.

   Let's try to figure out at least the courses. These thoughts will be useful for beginners and those who have just decided to join the diving community.