Gremlins in the cockpit! Please note that as a result of additional information from Japan I have had to significantly correct my original post on this subject on 31 March.
In that post I compared the similarity of the closest standard Munsell values for J3 and I3 as they related to the current appearance of aged and weathered artifacts. That comparison may have confused readers. The precise values from the original Kariki 117 and 8609 chips for these colours demonstrate a more significant difference and also reveal the changing appearance of J3 over time.
Please refer to the original post for further details and images.