diff --git a/doc/fixes37.0 b/doc/fixes37.0
index fce516d0a..9301c24ad 100644
--- a/doc/fixes37.0
+++ b/doc/fixes37.0
@@ -563,6 +563,8 @@ avoid complaints of "nothing to foo" for 'force_invmenu' if there are no
 	likely candidates to foo with but there are hidden acceptable choices
 avoid "Not carrying anything.  Never mind." for 'force_invmenu'
 'altmeta' option could be toggled On but once On could not be toggled back Off
+wearing a ring of protection and any amulet behaved as if wearing an amulet of
+	guarding when determining MC value
 
 curses: 'msg_window' option wasn't functional for curses unless the binary
 	also included tty support
diff --git a/src/mhitu.c b/src/mhitu.c
index 664c7cd4e..faf177388 100644
--- a/src/mhitu.c
+++ b/src/mhitu.c
@@ -902,7 +902,7 @@ magic_negation(struct monst *mon)
             if (armpro > mc)
                 mc = armpro;
         } else if ((o->owornmask & W_AMUL) != 0L) {
-            via_amul = TRUE;
+            via_amul = (o->otyp == AMULET_OF_GUARDING);
         }
         /* if we've already confirmed Protection, skip additional checks */
         if (is_you || gotprot)
@@ -917,7 +917,8 @@ magic_negation(struct monst *mon)
     }
 
     if (gotprot) {
-        /* extrinsic Protection increases mc by 1; 2 for amulet */
+        /* extrinsic Protection increases mc by 1 (2 for amulet of guarding);
+           multiple sources don't provide multiple increments */
         mc += via_amul ? 2 : 1;
         if (mc > 3)
             mc = 3;