diff --git a/Makefile.emscripten b/Makefile.emscripten
index 057ca03..f62735e 100644
--- a/Makefile.emscripten
+++ b/Makefile.emscripten
@@ -24,7 +24,7 @@ CXX = em++
 CXXFLAGS = $(DEFS) $(INCLUDES) $(EMFLAGS) -MMD
 
 LFLAGS := $(EMFLAGS)
-LFLAGS += -s EXPORTED_FUNCTIONS="['_main','_ags_setAntialiasedStringMode']"
+LFLAGS += -s EXPORTED_FUNCTIONS="['_main','_ags_setAntialiasedStringMode','_sjis2unicode']"
 
 all: doc/system3.js doc/system3.asm.js
 
diff --git a/src/sys/ags_text.cpp b/src/sys/ags_text.cpp
index 2b88d99..36810b0 100644
--- a/src/sys/ags_text.cpp
+++ b/src/sys/ags_text.cpp
@@ -538,4 +538,10 @@ void ags_setAntialiasedStringMode(int on) {
 	antialias = on != 0;
 }
 
+#ifdef __EMSCRIPTEN__
+int sjis2unicode(int byte1, int byte2) {
+	return s2u[byte1 - 0x80][byte2 - 0x40];
+}
+#endif
+
 }