In
letter 323 of on or about Saturday, 3 March Van Gogh says he is expecting several models ‘tomorrow’, among them a boy (
ll. 119-123 and
ll. 129-131); the present letter says that he began work on a watercolour with these models ‘this morning’. He also says: ‘Since I’ve been so busy writing letters of late, I’ll probably not write again before the tenth’
(ll. 104-106). On these grounds we have dated this letter to on or about Sunday, 4 March 1883. (Another point is that the children would have been most likely to pose on a Sunday.)