That's a very pretty nobile! Wish I had room to grow more Dendrobiums.

In the early days of nobile/softcane Dendrobium breeding other species were used and Rentoul says that some of the early breeding was shrouded in mystery.

I wonder where the colours on hybrids such as Yukidaruma 'King' and 'Queen' came from. Perhaps from a variety of the nobile species or perhaps from an infusion of other species.

Australia is a bit closer to the source than Brazil and the only nobile species seen here are the alba form and various forms of mauve colour.

This is not to say that your plant is not a variation of the species but it just illustrates the problems that crop up from time to time. In any case it is still a lovely flower.