Doomsday rule
Regla Doomsday
- Date
- 1973 · confidence high
- Place
- Cambridge, England, United Kingdom
- Credited to
- John Horton Conway
- Field
- Knowledge & symbols
What it is
John Horton Conway devised a mental calculation method that gives the day of the week for any date, based on "doomsdays" that always fall on the same weekday each year.
What it led to
- Mental date-calculation competitions
- Pocket perpetual calendars
- Popularization of modular arithmetic
- Software for date verification