Obtained from Jacques Marty and labeled 'Suisen', but clearly not polyploid; no thick petals and no inhibited fertility. Might be the diploid form Eiga-no-Homare or a diploid Suisen sibling like Hitomebore.
Mark Nijland extensively used this azalea in his breeding, obtaining nice results.
Probably is 'Sato no Hikari', possibly'Miyuki'.
Breeding code: u