The system of Czech participles contains an active preterite participle on -(v)ší, which according to standard grammars can only be perfective. In a sufficiently large corpus, however, it is possible to find several hundred instances of imperfective active past participles.
What are their functions? Is aspect opposition relevant or neutralised? Do participles show classical aspectual functions? This article gives some answers from a highly peripheral area of the Czech verbal system.