Not all types of foreign equity are exempt from tax in the first 5 years on HSP/J-Skip

I am moving to Japan on a J-Skip visa.

I was excited to read that, for the first 5 out of 10 years as an NPR, foreign equities don't incur capital gains tax as long as the gain is not remitted to Japan.

I assumed that this would include the equity I hold in my privately held business that is located outside Japan, which I plan to sell to a private buyer while a NPR in Japan.

To my surprise, this type of transaction is subject to tax on capital gains. Why? The equity needs to be 'sold outside of Japan' to qualify as foreign. And this is proven via:

Sold in foreign financial instruments markets 

Sold to a foreign financial instruments broker by agency trade

Sold of securities which had been safe-kept in an account at a foreign financial instrument broker or a foreign financial institution

(Source)

So, even though my company is outside Japan, the buyer will be located outside Japan and the transaction will only involve offshore accounts with no remittance, because the transaction didn't happen on an exchange or through a big institution, the transaction is subject to capital gains tax.

Just posting this edge case here as most Reddit threads just say that foreign equity sales in first 5 years = no tax.