Single digit kyu
Single Digit Kyu, in the range of 9k to 1k. Often abbreviated as SDK. Distinguished from Double Digit Kyu.
There is some ambiguity as to whether the terms "high single digit kyu" and "low single digit kyu" should be understood numerically (so that a 9k would be "high" and a 1k "low") or in terms of playing strength (9k "low", 1k "high"). The latter of these two usages appears to be more common.