  We report the observation of the decay Ds1(2536)+ -> D+ pi- K+. We also
measure the helicity angle distributions in the decay Ds1(2536)->D*+ K0S and
thus constrain the contributions and the phase difference of D and S wave
amplitudes in this decay. The results are based on a 281 fb^-1 data sample
collected with the Belle detector near the Y(4S) resonance, at the KEKB
asymmetric energy e+e- collider.
