diff --git a/1986/marshall/Makefile b/1986/marshall/Makefile
index 44dbc46bc..13ac7b81f 100644
--- a/1986/marshall/Makefile
+++ b/1986/marshall/Makefile
@@ -69,7 +69,9 @@ CINCLUDE=
 
 # Optimization
 #
-OPT=
+# We DISABLE the optimiser due to funny problems in different compilers and
+# systems. See compilers.md for more details on this problem.
+OPT= -O0
 
 # Default flags for ANSI C compilation
 #
@@ -132,8 +134,10 @@ all: data ${TARGET}
 	clean clobber install love haste waste maker easter_egg \
 	sandwich supernova deep_magic magic charon pluto
 
+# We FORCE disable the optimiser due to funny problems in different compilers
+# and systems. See compilers.md for details.
 ${PROG}: ${PROG}.c
-	${CC} ${CFLAGS} $< -o $@ ${LDFLAGS}
+	${CC} ${CFLAGS} -O0 $< -o $@ ${LDFLAGS}
 
 # alternative executable
 #
diff --git a/1986/marshall/README.md b/1986/marshall/README.md
index 2fe2ce2fb..dd98343e8 100644
--- a/1986/marshall/README.md
+++ b/1986/marshall/README.md
@@ -4,6 +4,10 @@
 make all
 ```
 
+
+NOTE: we FORCE disable the optimiser due to a funny problem with different
+compilers and systems. See below and [compilers.md](compilers.md) for details.
+
 There is an [alternate version](#alternate-code). The reason is a funny problem:
 in modern systems, depending on the platform, compiler and the optimiser, it
 would work with one compiler with the optimiser but it would not work with the