pikendate

Pikendate is a fictional date notation system used in worldbuilding and speculative fiction. It is not a real calendar, but a constructed framework that some authors and game designers use to coordinate chronology across multiple eras. In most treatments, a pikendate encodes three elements: an era code, a year within that era, and a day within the year. The era code is typically a short uppercase string, followed by a hyphen. The year within the era is a numeric value, commonly four digits, and the day within the year is a three-digit index from 001 to 365 (or 360 in some variants). A representative form is PN-021-075, read as: era PN, year 21, day 75 of that year.

Because pikendate is not standardized, different worldbuilders may extend the format with additional fields, such as month names, leap-day rules, or a separate time-of-day component. Some variants use a fixed 360-day year with 12 months of 30 days, while others allow a 365- or 366-day year with leap days; some adopt era-start offsets to align with historical events. In practice, pikendate is favored for its lexicographic sortability and ease of conversion to other calendars.

In use, pikendate is typically accompanied by a reference calendar describing era lengths, leap rules, and mappings to real-world dates when applicable. It is commonly employed in large-scale worldbuilding projects, role-playing game backstories, and fictional histories.