I am technically a certified 'Reiki Master' which is of course Japanese in origin. So, I work with the energy body a lot, daily really.
The Nadi system actually is just sophisticated and developed as the meridians, there are just not as many works available on it. They have 'mapped' the Nadi just as they have the meridians.
Also there are no 'chakras' exactly in Qi Gong but there are 'gates' and I have found that they largely line up with the 'front' and 'back' of the 'chakras', so I would actually suggest they have discovered the same system but have examined different parts of it in detail.
http://www.subtleanatomy.com/Nadis.htm
The Nadi system actually is just sophisticated and developed as the meridians, there are just not as many works available on it. They have 'mapped' the Nadi just as they have the meridians.
Also there are no 'chakras' exactly in Qi Gong but there are 'gates' and I have found that they largely line up with the 'front' and 'back' of the 'chakras', so I would actually suggest they have discovered the same system but have examined different parts of it in detail.
http://www.subtleanatomy.com/Nadis.htm