The Stackz flashcard visualization concept helps to keep the overview over a large amount of words to be learned by representing your current proficiency state with one intuitive view using piles of colored flashcards. The Karten are distributed according to the 'mastery level' and colored according to the 'date of the last mastery' - they become darker over time. Thich system allows to distinguish easy Karten from difficult ones immediately, and simultaneously seeing which Karten must be refreshed because they have not been reviewed for a long time.

Stackz supports any other unicode lanugage of the Widows operating system as well. The constantly growing online wordlist archive currently contains over 200 wordlists for Japanese, Chinese, Korean or Thai.

A Pocket PC version of Stackz is also available, bringing the Stackz flashcard system to virtually any place. The wordlist files can be directly downloaed to the Pocket PC, which guarantees seamless synchronization of the learning status between the platforms.