CREATE TABLE table_203_392 (id DECIMAL, "rank" TEXT, "belt alternate 1" TEXT, "belt alternate 2" TEXT, "belt alternate 3" TEXT, "belt alternate 4" TEXT)

which kyu levels have only one color belt ?
SELECT "rank" FROM table_203_392 WHERE "belt alternate 2" IS NULL
SELECT "rank" FROM "table_203_392" WHERE "belt alternate 2" IS NULL