RHS shows the parents as Den moniliforme x Den regium
There is no registration of a Den moniliforme Raikomaru so if used the 'Raikomaru' should be in quotes. There is no awarded clonal variety 'Raikomaru' so it has no meaning except to the breeder. Possibly it was awarded very recently or the breeder hopes to get am award int he future.
The AOS magazine a few years ago had an article recommending giving every division or seeding a clonal name in case the plant was awarded in the future.
Raikomaru is a cultivar name (defined by appearance, not genetics)
it should be written Den. moniliforme cv. Raikomaru
the clonal name, if it had one, would go after the cultivar name. This system is fairly common with japanese orchids, and the cultivar names are usually registered with the Japanese Fukiran Society. Another example of this naming system is:
Neofinetia falcata cv Monohime 'New World Princess' CHM/AOS