“Card catalogs” were kept with the utmost diligence, with all vital information on every prisoner – age, health, education, skills, work experience – all used to put each prisoner to work in a job at the highest possible skill level.
The same system was used for all Germans, to put them all to work in the most efficient possible way. We call that management these days. Workers call it job satisfaction. Stockholders call it profits and productivity.
IBM helped the Nazis with all these catalogs. One such application was to assemble all the genealogical records going back at least three generations, especially religious affiliations. Without IBM’s, albeit primitive, computers; well, the designation of “Jew” would have applied to very few Germans indeed.
If nothing else; and nobody denies; the Nazis were obsessive at keeping precise, detailed records. And they were righteously diligent about following the letter of the law.
The laws designating a person as a “Jew” were unambiguous. They were not, actually, based on race at all. The laws were based on religious practice. A parent or grandparent had to have been a practicing Jew, regularly attending services, etc. – to be classified as a “Jew.”
Thus, it was the Jews’ own records that were used to classified parents and grandparents as Jews, and thereby their descendants as “x part Jew.” Nobody kept records of religious participation but the Jews themselves, in the synagogue archives.
Sure, the local municipality had birth and marriage records. But it was insufficient if two secular Jews were married and had offspring. Only if they were observant, religious Jews; that’s what mattered to the Nazi bean counters, and just that.
Ironically, the widespread burning of Jewish synagogues during Kristallnacht “The Night of Broken Glass” in November 1938 was a frustrated effort by the German people to destroy the synagogue records that were being used to categorize Jews.
The burning question remains: Why didn’t the Jews just get rid of those records, bury them, put them in a Swiss bank vault; anything to keep the Nazis from getting ahold of them.