World Notes WEST GERMANY

Willy Brandt, who served as West German Chancellor from 1969 to 1974, has always enjoyed a reputation as a moody, unpredictable politician. He lived up to that billing last week when he abruptly quit his post as chairman of the Social Democratic Party. A stone-faced Brandt informed his colleagues he was resigning his position because of the "internal criticisms" of his leadership.

Brandt, 73, who had been SPD leader since 1964, fell victim to the intense feuding between leftists and moderates that has virtually paralyzed the party. The crowning controversy was his effort to appoint a 30-year-old Greek emigre named Margarita Mathiopoulos as the party's chief spokeswoman. Not only did she not belong to the SPD, she was not even a German citizen. Brandt's successor will be Hans-Jochen Vogel, 61, the party's parliamentary leader.