Andrew Embick's Fast and Cold: A Guide to Alaska Whitewater describes the Chakachamna River as "Unrunnable for about five miles at all but the lowest flows, plus whatever amount of Class VI you care to try." With a description like that, it's no surprise that few kayakers attempt the run.
However, a hair-raising guidebook description isn't enough to stop everybody. The river has been run in its entirety several times since Fast and Cold was released, but still remains largely unknown to the wider whitewater community. Eric Parker and Brendan Wells decided to check it out for themselves, and documented their journey in spectacular fashion. For more information, read Parker's blog entry on the trip here.