Pocket Fritz, which is at version 4, is a chess playing program for Pocket PC personal digital assistants (PDAs). Pocket Fritz 4 uses HIARCS as the chess engine. Pocket Fritz 2 used a port of the Shredder chess engine.
Since the popularity of the PDA came about in the 1990s, some chess programs have been written for the portable market. This has also been in response to the increased popularity of chess in recent years.
Commonly available chess programs in PDAs are of mediocre quality. In a very thorough and comprehensive review of 63 chess programs for PDAs by Dr. Axel Schumacher, he found some did not even know the rules of chess, with at least one moving the king, then castling. Pocket Fritz 2 was rated third in that review, behind Pocket Grandmaster (commercial) and CE Board (free, but not open source). HIARCS v9.5 for Palm was rated number 5 in that review, although that was the first program on a PDA to beat a grandmaster, when on January 22, 2005 it beat GM Jan Gustafsson twice, and drew twice in a four-game match. However, pure playing strength is not the only indicator of the quality of a chess program. The quality of the graphical interface is important, with many programs being very poor indeed. Pocket Fritz 2 claims to have an estimated blitz performance rating of 2450 Elo points.
The strength of chess programs on PDAs will unlikely be as strong as on larger computers, due to the slower processors and more limited memory. The only way in which the strength of chess programs would be as strong as that on larger computers is if the game of chess were to be solved to all valid permutations. Under these conditions, ceteris paribus, all programs would perform perfectly on all machines.
The web page for Pocket Fritz 2 states that the program can connect to the Chessbase server and allow you to search for the current board position in more than 2 million games on the server. This is no longer true, as that functionality was broken in early 2006 by changes on the Chessbase server. According to Chessbase a high priority to fix, as was detailed in an email to Dr. David Kirkby part of which is shown on one of the chess newsgroups.
The Pocket Fritz 4 won the Copa Mercosur tournament in Buenos Aires, Argentina with nine wins and one draw on August 4-14, 2009. The 2009 Copa Mercosur tournament was a category 6 tournament. The Pocket Fritz 4 achieved a performance rating 2898. It uses chess engine HIARCS 13. The Pocket Fritz 4 was running on the mobile phone HTC Touch HD. Pocket Fritz 4 searches fewer than 20,000 positions per second.