How strict is the ass-in-Japan-for-6-months rule for my work visa?

I travel a lot for work. But on my visa, I need to be in Japan for 6 months + 1 day to be considered a full time employee.

Does anyone know how strict this rule is enforced? Do they check? I’d really like to make a trip for work in DC but might be able to attend depending on how strict this rule is.