Konjunktiv II is used to express hypothetical, unreal, or wishful situations in German. The deck highlights essential irregular forms that learners should memorize: ich ginge (gehen), er käme (kommen), ich wüsste (wissen), er ließe (lassen), ich bräuchte (brauchen), ich fände (finden), es gäbe (geben), ich nähme (nehmen), ich stünde/stände (stehen), and ich zöge (ziehen). These archaic-sounding stems often appear in formal writing; in everyday speech, however, speakers usually prefer the periphrastic würde + Infinitiv construction to avoid them. Konjunktiv II also drives conditional sentences (Wenn ich Zeit hätte, würde ich kommen) and polite, indirect requests.
Konjunktiv I, by contrast, is primarily used for indirect or reported speech, especially in journalism and formal writing. Each verb forms Konjunktiv I by taking a characteristic stem and the personal endings: ich sei, du sei(e)st, er/sie/es sei, wir seien, ihr seiet, sie/Sie seien (sein); er habe (haben); sie könne (können); er werde (werden, used to report future statements). The general pattern for reported speech is "[Subject] sagte, [Konjunktiv I clause]."
A subtle complication arises whenever a Konjunktiv I form coincides with the indicative — for example, sie haben looks the same in both moods. In such cases, formal usage falls back on Konjunktiv II (here, sie hätten). The verb sein is uniquely reliable because all its Konjunktiv I forms differ from the indicative, which is why it remains the safest choice across all persons in reported speech.