The Gi and Hakama should be washed per hand and treated with fixing salt before being worn. This prevents the color of the material from bleeding too much..
You should place the jacket and slacks in the bath or shower, folded, and stomp on them bare foot, as used to be done in wine production. This conserves the material, and the creases in the Hakama retain their distinct form when it is hung to dry. [click heren].
The Gi and Hakama should also be washed this way after the first washing, then, of course with washing detergent rather than fixing salt. It is not advisable to wash the clothing in a washing machine, because the form of the material then severely suffers. You should especially note that high quality clothing will be ruined if washed in a washing machine!