Designated Activities (long stay for recreation) Visa

Hello,

I’m interested in the Designated Activities visa for Long Stay and Sightseeing. My main concern is the 30M JPY requirement.

Is it a requirement that the funds be held in an account for at least 6 months prior to applying for the COE? If so, what type of account is recommended? I’d like to avoid the opportunity cost of just parking it in a savings account for 6 months.

Thanks!