Gosho Zenshu p. 1546
Now in the Latter Day of the Law,
neither the Lotus Sutra nor the other sutras
lead to enlightenment.
Only Namumyohorengekyo can do so. . . .
To mix other practices with this
Namumyohorengekyo is a grave error. . . .
Good medicine works by itself, there is no need
to add other medicine.