How to memorize the eternal calendar

- Supplementary description -

The words for memorizing the month codes:

I tried to find short words that begin with the same character as the month names. But to avoid confusing the words for months that start out with the same character (January/June/July, March/May), the words for these months contain 2 or 3 of the first characters of the month's name. The first consonant that's different from the month name represents the information for the number to memorize. Further characters in the word (in "Familie" the characters after the "m" for 3) are to be neglected.

Usage: If you hear the month name (e.g. "May"), you remember the word associated ("Maid") and decode the month code from the first consonant of the word that differs from the month name ("d" --> 1).

The words for memorizing the year codes:

The words to memorize the years are made up from the two last ciphers of the year plus the number to associate. If they contain additional sounds: neglect them!

Usage: You want the code for a leap year (e.g. 1972): Take the last two ciphers (72), encode them with the Major scheme (72 --> k n), remember the word that begins with these sounds ("Kanal"). Take the next relevant sound ("l") and decode it (L --> 5)

Leap years:

All years that can be divided by 4 are leap years. But all years that can be divided by 100 are not leap years. But again those years that can be divided by 400 are leap years.

Properties of the year codes:

year ---> year + 1: +1 (normal year), +2 (leap year)

year ---> year + 4: -2 (in 20th and 21st century)

year ---> year + 28: +/- 0 (in 20th and 21st century)

Ways of finding the year code:

1. You remember the codes for 28 consecutive years (e.g. 1972 - 1999). Add/subtract 28 until you obtain a year that is within the range you know. The code for the two years are identical. (Example: 2005 --> - 28 = 1977 --> year code = 5)
2. You remember the codes for leap years.
   1. You know the leap year before the wanted year: add the year difference + 1 to the code wanted: 2005, known: 2004: 3, --> code for 2005 = 3 + 1 (difference) + 1 (leap year) = 5
   2. You know the leap year after the wanted year: subtract the year difference from the code wanted: 2005, known: 2008: 1, --> code for 2005 = 1 - 3 (difference) = -2 = 5 (mod 7)

Examples:

June 20, 1996:                     December 15, 1970:                         
20 day                             15 day                                     
4 June (Junior -> R = 4)           5 December (Delle-> L = 5)                 
0 1996 (Beschuß > ß = 0)           3 1970 (1972 = Kanal = 5 > -2 (years) =    
1 leap year                        3)                                         
-------                            0 no leap year                             
25 = 4 (modulo 7) --> Thursday     -------                                    
                                   23 = 2 (modulo 7) --> Tuesday