  We describe a protocol to prepare solitons in a quasi-1d box-trapped
Bose-Einstein condensate using only a quench of the isotropic s-wave scattering
length. A quench to exactly four times the initial 1d coupling strength creates
one soliton at each boundary of the box, which then propagate in a uniform
background density and collide with one another. No nonsolotonic excitations
are created during the quench. The procedure is robust against imperfections in
the scattering length ramp rate and a mismatch of the final scattering length.
