On a five string bass, the notes across the fret board follow the circle of fourths exactly. So if you know the notes chromatically on the "B" string, you know the notes on the bass (if you know the circle of fourths). Open strings B, E, A, D, G--First fret C, F, Bb, Eb, Ab,(or the Sharp equivalent)--Second fret Db, Gb, B, E, A. Guess what the third fret on the B string is. And then, of course (D) G, C, F, Bb, going across. Fourth fret, Eb, Ab, Db, Gb, B and on and on. When you get to the twelvth fret, it all starts over. Studybass.com has a very good tool for learning the fret board as well. it is free.