From The Destruction of the European Jews by Hilbel - more than you ever want to know.
Trust the Germans to make things complicated: The original decree said anyone who had at least one Jewish grandparent (or practiced the Jewish faith) Then there was subsequent clarification. Everything was done with laws, including provisions for “aryanization” of Jewish businesses, Jews were forced out professions (doctor, performer, anything) because doing certian jobs required license from offical organizations and Jews were denied licenses as non-citizens. Everything was done by precise laws, although state violence against jews was not prosecuted.
The Losener proposal was incorporated into the First Ordinance to the Reich Citizenship Law, dated November 14, 1935.15 In its final form the automatic sorting method separated the “non-Aryans” into the following categories: Everyone was defined as a Jew who (1) descended from at least three Jewish grandparents (full Jews and three-quarter Jews) or (2) descended from two Jewish grandparents (half-Jews) and (a) belonged to the Jewish religious community on September 15, 1935, or joined the community on a subsequent date, or (b) was married to a Jewish person on September 15, 1935, or married one on a subsequent date, or (c) was the offspring of a marriage contracted with a three-quarter or full Jew after the Law for the Protection of German Blood and Honor had come into force (September 15, 1935), or (d) was the offspring of an extramarital relationship with a three-quarter or full Jew and was born out of wedlock after July 31, 1936. For the determination of the status of the grandparents, the presumption remained that the grandparent was Jewish if he or she belonged to the Jewish religious community
Then they get into Misclings of first and second degree -
Defined not as a Jew but as an individual of “mixed Jewish blood” was (1) any person who descended from two Jewish grandparents (half- Jewish), but who (a) did not adhere (or adhered no longer) to the Jewish religion on September 15, 1935, and who did not join it at any subsequent time, and (b) was not married (or was married no longer) to a Jewish person on September 15, 1935, and who did not marry such a person at any subsequent time (such half-Jews were called Mischlinge of the first degree), and (2) any person descended from one Jewish grandparent (Mischling of the second degree). The designations “Mischling of the first degree” and “Mischling of the second degree” were not contained in the decree of November 14, 1935, but were added in a later ruling by the Interior Ministry.17 In practice, therefore, Losener had split the non-Aryans into two groups: Mischlinge and Jews. The Mischlinge were no longer subjected to the destruction process. They remained non-Aryans under the earlier decrees and continued to be affected by them, but subsequent measures were, on the whole, taken only against “Jews.” Henceforth the Mischlinge were left out.
As an example, there were specific laws by 1938 on how to buy out Jewish businesses, limiting prices and how the resulting broken contracts (i.e. contract with another jewish business) were to be paid. So someone could not just walk in and take a business, there was a formal sale. A sale was required, but it had the trappings of a legal contract. The law limited prices because they Nazis found that too many businesses were competing to buy out Jewish competitors, bidding up the price (anf giving Jews too much money).
All the vicious nastiness of the Nazi ideology was carefully wrapped in legal niceties to appear legitimate.By removing citizenship from Jews, they could fall back on the premise that non-citizens were unreliable and could not participate in assorted parts of German society.