A window is a rule with context
Some products appear on a rolling basis, some are released in batches and others depend on a draw, event calendar or seasonal timetable. Treating them as one universal “book X days before” rule creates false confidence.
Record the fields that matter
- the visit date you are targeting;
- the stated release date and time in Japan;
- the timezone you will be in when booking;
- the official channel and any account preparation;
- the date on which you last verified the rule.
This project leaves the calculation empty whenever the official source does not publish a precise, current rule. Those entries remain useful live-check tasks without creating a false deadline.
Expect change
Operators can change sales systems, maintenance dates or eligibility. Every experience links its source and checked date; recheck the official page shortly before the reminder and again before payment.