Of course there are Atlases in the library (Annie keyword search: 'atlas and china', and 'atlas and japan').
There are lots of maps on the Web, generally in the form of .jpg and .gif graphics; there are also many map servers which offer some level of interactivity --allowing the user to zoom, query, and perhaps turn map layers on and off (see an example for Hong Kong). Just what the possibilities are in the realm of East Asian Studies is an interesting question... and I have some of the answers, but would like to find more. How shall we set about drawing up a catalog of resources?
Our strategies must surely include some Web searching... but it's pretty clear that we're looking for several distinct sorts of things:
china "online atlas" google search is a pretty good start, and here are some of the results:
Map of current SARS cases in China --see also Mapping SARS, and ESRI's SARS GIS
China Virtual Tours (may have maps...)
CIA topography map
china geography google search
geography.about.com
China Geography Specialty Group (see links at bottom)
China Dimensions CIESIN
And some sources for Japan:
JAPAN GIS/MAPPING SCIENCES RESOURCE GUIDE and DIGITAL GEOSPATIAL DATA SOURCE DIRECTORY
Japanese Historical Maps from UC Berkeley
Japan Atlas from Japan Information Network