Modified RegisterThe Modified Register system is similar to the Register System but gives every child an assigned number. Persons who are continued in the next generation have the plus sign (+) to the left of their number.
Henry (two variations)The Henry System is named after Reginald Buchanan Henry. He used it in his 1935 book Genealogies of the Families of the Presidents. Basically this is a "birth order by generation" numbering scheme. The starting person (aka. the progenitor) is number 1. His first child is number 11. His second child is number 12. And so on for each child of the progenitor. Then, the first child of the progenitor's first child is number 111. The second child of his first child is number 112. The first child of the progenitor's second child is 121. And so on. If there is a tenth child, the letter X is used. If there is an eleventh through the thirty third child, they use A through W respectively.
Note that a second variation exists. This applies only when a given person has ten or more children. Instead of using the letters X then A through W, the actual two-digit numbers are used. When used, they are enclosed in a set of parenthesis. Thus, instead of Henry number 12X5 it would become 12(10)5.
Modified HenryThe Modified Henry System is similar to the Henry System except that the persons are not divided by generation. Instead, all descendants for the first child are given, then all descendants for the second child are given. And so on. In this fashion, all of the numbers are completely in ascending order.
AhnentafelThe Ahnentafel System is used only for the direct ancestors (ascendants) of a given person. The starting person is assigned number 1. The father is assigned number 2. The mother is assigned number 3. To continue with all other generations, the number of the father of a person is twice the value of the number of the person. The number of the mother of a person is twice the number of the person plus one.
To see an example, click here.
d'AbovilleThe d'Aboville System is very similar to the Henry System. The difference is the use of periods between the value for each generation.
AscendancyThe Ascendancy System lists all ancestral fathers of the person along with a number (usually as a superscript) of the generation number of each father.
Example of two brothers:
To read some web articles concerning the use of genealogical number systems, see www.cyndislist.com/organize.htm#Numbering.