Koujien and Daijirin are THE authoritative Japanese dictionaries. Koujien has over 230,000 entries. It's not a Japanese-English dictionary--the keywords, definitions, and usage notes are all in Japanese. Consider it the Japanese version of the Concise OED or that 5 inch thick American Heritage that keeps your desk from floating away. For advanced students, the wealth of example sentences and usage notes is essential. For less advanced students, however, it may be difficult to use, and non-academic users of Japanese probably won't find much use for it. Most non-Japanese might find Daijirin, with its greater emphasis on contemporary Japanese, more helpful. Take a look at the screenshots below, all showing fairly typical entries selected at random, and decide for yourself if Koujien is worthwhile for you. The usual caveat about screenshots not looking as good as the actual PDA display applies--see below.
You can also take a look at the publisher's page and an English description of Koujien from Wikipedia.
Koujien is not available as a download, so with your order you'll not only get Koujien on your card or PDA, you'll also get the original CD and dcoumentation.
Click an image to see it at full VGA size.
For information on how to use the EBPocket software and the PDA itself, see the general documentation.
Note that I've sized the images above to appear about the same physical size as the Axim X50V's screen (depending on your monitor, of course); however the actual Axim screen squeezes a full 480x640 pixels into that space, so it's much sharper and easier to read (more pixels in the same size=higher resolution). You can click each image to see the actual 480x640 pixels you'd get on the screen of an Axim or other VGA PDA, although because the image will then be much larger than on the Axim screen it still won't look quite as sharp as the real thing. And of course you can change the text size to be larger or smaller, too, which will also affect legibility.