Raku is a kind of pottery where the clay is made in a fire pit. Raku is often still porous and not water tight.
A raku voucher request is one which is signed by the pledge only.
A bisque firing in pottery is done at a high temperatire and seals the clay, making it water-tight and ready to accept colour.
A bique voucher request is one which is signed by the JRC, and contains a prior-signed-voucher-request that contains a raku voucher request.