Basic German adjective endings not making sense!

[Cainntear]

The way I remember it from my German classes:
definite article → weak declension
indefinite article (+mein, dein ..., kein) → strong declension

To me, this makes sense. The definite article is already "strong" (or informative) enough, so the adjective can remain weak.

You should slightly revise your memory. Indefinite article (+mein, dein ..., kein) is mostly "strong" too (in the declension table only 3 out of 16 cells are without endings), so the adjective after it is mostly weak (also known as "mixed" in grammar manuals). Strong adjectival declension is when there's no articles (or possessive/negative pronouns, etc.) whatsoever before the adjective.

edit:
I said "revise your memory", but I didn't think that it could have been how they actually taught you. Is that actually true (that they used to teach that after the indefinite article the declension of the adjective is strong)? This terminological convention doesn't make sense to me, tbh.

Ah... Strong, weak and mixed... That definitely rings a bell -- I read that back a long time ago (when I was reading about German -- I never got fat enough to put it in my language list).

Thanks for that -- I engage in conversations specifically to further my own understanding, so am usually very pleased to be shown how and where I'm wrong. I haven't deleted my previous post, but just struck out the text to show it's not to be taken as information by anyone else.

[Cainntear]

To me it feels kinda more intuitive to see all the positions in a declension as declined, but some with the 'empty' morpheme Ø.

Or perhaps that the strong vs weak vs mixed is not about whether it's declined at all, but which variables it's declined for...?
eg. a weak declined adjective appears to only declined to indicate grammatical role (attributive adjective as opposed to predicative) and a strong one is also declined for grammatical gender? Am I getting that bit right?

[Iversen]

Occam's razor tells me to maintain that the adjective always is declinated when used attributively in High German, but sometimes the ending is zero and sometimes the same endings are used across gender borders. I can't see that the attempts to separate declinated and declinated domains make the total picture clearer - you still have to learn the correct forms.

There is however a rule of thumb that says that the endings of the adjective get more uniform when a definite article is present with all its informative tidbits, and if the endings without exception coalesced into for instance -en then you could drop the corresponding parts of the charts - but German isn't quite there yet. But at least it has dropped the gender and case differences in the plural in favor of the ending -en (strong as well as weak attributive uses). In Icelandic and Faroese the neutralization has so far only happened in the genitive and dative strong plural - but at least the islanders have agreed to just use -u for ALL forms in the weak plural cases.

[Carl]

The invaluable and irreverent Emanuel of Your Daily German has a useful three-part series on adjective endings that takes a lot of the thinking out of it. You can find it here: https://yourdailygerman.com/german-grammar-course/

He says the first trick will help 50-60% of the time, without any grammar. The second trick will help 75-80% of the time, with minimal grammar. The third part will get you to 100%, and it's complicated enough that he recommends waiting until you're at B2 to read it.

Trick 1: Just add "-e"
Trick 2: Use “-en” whenever the article is weird.

Read the articles for more explanation.