  The Kohnen plus space, roughly speaking, is a space consisting of modular
forms of half integral weight with some property in Fourier coefficients. For
example, the $n$-th coefficient of a normal modular form of weight $k+1/2$ in
the plus space is $0$ unless $(-1)^kn$ is congruent to some square modulo $4$.
The concept of plus space was initially introduced by Kohnen in 1980. Eichler
and Zagier showed that the plus space is isomorphic to the space of Jacobi
forms in the one variable case. Later, Ibukiyama generalized these results to
the cases for Siegel modular forms in 1992. Also, Hiraga and Ikeda generalized
these results to the cases for Hilbert modular forms in 2013. In this paper, we
continue to consider the case of Hilbert-Siegel modular forms. An analogue of
the previous results will be given.
