Best Research Organization with Genealogy Numbering Systems

As I develop a filing system, I will be uniquely identifying those individuals that I truly want to further track. There are numerous genealogy-based numbering systems that are based on tracking the direct line ancestors OR tracking the descendants of a single progenitor. I would like to find or develop a system that works for me to track BOTH.


For ancestry, or pedigree, we have what is typically called the Ahnentafel ( system. With Ahnentafel, every direct line ancestor gets assigned a unique number. If Person = n, then Father is 2n and Mother is 2n+1.

If I am 1, then my father is 2=2*1 and my mother is 3=2*1+1. My mother’s father (Poppy) is 6=2*3(Mom) and her mother (Mimi) is 7=2*3(Mom)+1. Poppy’s parents are 12 and 13. Mimi’s parents are 14 and 15.

Ahnentafel will allow me to track all my direct line ancestors.


What about going in the other direction? For descendants, there are numerous systems: Register, NGSQ, Henry, d’Aboville.

The one that appeals to me is d’Aboville (’Aboville_System). It starts with a progenitor numbered 1. Children are numbered 1.x where x is the child number (or perceived order). 1.1 would be the oldest child while 1.3 would be the third child born. Grandchildren are numbered 1.x.y, where x is the child number and y is the grandchild number. The numbering identifies a path and creates an absolute unique number.

For example, if we started with my paternal grandfather as 1, then his three sons would 1.1, 1.2, and 1.3. Dad was the youngest, so as we look at me and my brother, we would be 1.3.1 and 1.3.2. Uncle Ed, the middle child, begat three children who would be 1.2.1, 1.2.2, and 1.2.3.


For some reason, d’Aboville and the other descendant oriented systems always start with 1 (one). That makes the first number in the notation really unused. I care about the descendants of each of my direct line ancestors. Perhaps I use the ahnentafel number as the progenitor number in d’Aboville.

I will start with myself as 1, thus making my children 1.1 and 1.2. My father is 2 and my mother 3. My brother is 2.2 as I was the eldest of the two of us. His kids are 2.2.1 and 2.2.2. Mom’s parents are 6 and 7. My mother’s brothers are 6.1 and 6.2 as she was the youngest of the three of them. My cousins are 6.1.{1..4}. Their children are and 6.1.3.{1..3}.

This shows promise for assigning numbers to all my direct line ancestors, the simple ahnentafel number. Anyone in my tree with a single number is a direct line ancestor. Using the dotted notation of d’Aboville, anyone with multiple numbers are extended family (cousins).

But, wait!

This means that some people would have multiple numbers? For example, I am 1, but I am also 2.1 as Dad’s oldest child. But I am also 4.3.1, because starting from Grandpa (4), Dad is Grandpa’s third child (4.3) and I am Dad’s eldest (4.3.1). So, I am 1, 2.1, and 4.3.1. And, I am just getting started.

I will keep this simple:

  • Direct line ancestors will be a single number.
  • Blood-line cousins will have a dotted notation (use the “nearest” or “shortest” number).

Those without numbers

What about the in-laws? For my research, while I care about the spouses of the above people, I am less interested in investing time in further research around those folks. They will exist in my database but will not be assigned a number.


I do plan to research a few in-laws. First is my wife, Natalie, who I will number in the same way by prepending an S to her ahnentafel numbering. She will be S1 and her parents S2 and S3. Her sister and brother will be S2.2 and S2.3 as she is the eldest.

My daughter Elizabeth just got married, so I intend to research her husband’s line. He will he dubbed E1 with his parents being E2 and E3.


By combining ahnentafel and d’Aboville, I am able to uniquely identify those people in my tree that I want to fully research and document. While this system looks promising for me, I would encourage others to explore the various genealogical numbering systems to come up with one for themselves.

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