During the development of early dive watches from Rolex, there was still some experimenting going on in regards to the dial writings, colours and references. This 6536 considered to be part of the early batch of dive watches actually having the name Submariner on the dial is a perfect example of this. With a very early serial number of 5 digits, it features the reference 6538 crossed out in the back and replaced with the reference 6536. Furthermore it features the depth printed in red which would very soon be discontinued in favour of all gilt graffics. The dial also has the characteristic 6 o clock marker that is in a slightly whiter shade than the rest of the indexes, insuring its authenticity. A rare insight to the world of early Rolex Submariners.