Large BCFT moduli in open string field theory

We use the recently constructed solution for marginal deformations by one of the authors, to analytically relate the BCFT modulus (λBCFT) to the coefficient of the boundary marginal field in the solution (λSFT). We explicitly find that the relation is not one to one and the same value of λSFT corresponds to a pair of different λBCFT’s: a “small” one, and a “large” one. The BCFT moduli space is fully covered, but the coefficient of the marginal field in the solution is not a good global coordinate on such a space.