I guess we need to establish that this really is Euonymus japonicus. The reason I think it is, is that it looks so much like a larger version of the E. japonicus 'Heespierrolino' in the Identification: - Small shrub, tough white new leaves, scallopped edges thread, except there isn't any white. It has an upright habit, dense branching, many short twigs though a few quite long ones, and the leaves seem to be obovate. For so long, I've noticed this plant but had no idea what it was, and then today I thought "I almost know this plant". I wouldn't even care so much, except that so many very different looking plants are E. japonicus, it seems like you'd need a cultivar name to even have any idea what you're talking about. I see a cultivar called 'Benkomasaki' (syn. 'Benkomoki'), but that's in France and seems to have longer branches. The cultivar 'Microphyllus' also seems to have longer branches and thinner leaves.
The common one down here is this: https://usna.usda.gov/assets/images/as_standard_image/Euonymus_japonicus_Green_Spire.pdf At first it looks like the plant in your pictures.
Thank you for the reply and the link! Interesting to read that that the properly named Euonymus japonicus 'Green Spire' was originally called " Euonymus japonicus Bekomasaki, a Japanese descriptive name of no botanical standing." The close-up leaf photo does look very much like it. The plant in the habit photo is very striking. I hope this grows to look like that! It was supposed to flower this month. I don't think it did.
What would seem to actually be Japanese common names becoming western cultivar names after material is imported is a recurring circumstance. Presumably due to a different commercial tradition there, regarding horticultural naming. In addition sometimes Japanese companies specifically interested in exporting to the West have coined new names for western distribution, that are different from those being used in Japan. On top of the apparently profit motivated generation of spurious cultivar names that has long gone on already in western countries. Regarding the 'Heespierrolino' for instance I saw what could perfectly well be the same clone at Home Depot recently, with a completely different, more conventional (accessible) cultivar(?) name on it (no quotes or any other designations were used so I couldn't be certain if I was looking at a cultivar name or trademark). Either somebody has applied their own naming to 'Heespierolino' or there is a lookalike plant of independent origin on the US market.
