I don't think that is Yata No Kagami, I have a number of them and the flower is much darker though the flower color does vary some.
This is Yata No Kagami.
You can have all the flowers go pale. The egg-shape pattern can get so dominant that it leaves you with only reddish tips. Just like the flower in the OP.
Because I remembered that Clicio had a labeled Yata no Kagami, this was my guess. Also, because they can compare this one to the labeled Yata no Kagami and compare flower shape or leaf shape.
Also, I saw there were more flower buds on this plant. But it could be this is a pale sport that no longer can produce the solid reds and red with tamafu.
I also thought it may be Yata no Kagami because of the flower shape, the stamen count (though 5 is extremely common) and the colour and positioning of the blotch.
If you'd argue that we should probably call it 'Shinkyo' instead, fine sure.
Since tsumabeni is not very common, I'd say Yata no Kagami is still a good guess.
What other common satsuki have tsumabeni and have this flower shape (elongated petals)?
Actually, for the plant labeled 'Yata no Kagami' I am surprised how rounded and ruffled the petals are. That is non-standard.
The 'Akemi no Tsuki' seems correct.