diff -Nbaur nethack-3.4.3/src/monmove.c nethack-cosh/src/monmove.c
--- nethack-3.4.3/src/monmove.c	2003-12-08 10:39:13.000000000 +1100
+++ nethack-cosh/src/monmove.c	2007-05-21 12:50:17.000000000 +1000
@@ -1278,7 +1278,8 @@
 
 	/* without something like the following, invis. and displ.
 	   are too powerful */
-	gotu = notseen ? !rn2(3) : Displaced ? !rn2(4) : FALSE;
+	gotu = notseen ? (Stealth ? !rn2(4) : !rn2(3))
+                       : (Displaced ? !rn2(4) : FALSE);
 
 #if 0		/* this never worked as intended & isn't needed anyway */
 	/* If invis but not displaced, staying around gets you 'discovered' */
diff -Nbaur nethack-3.4.3/src/objects.c nethack-cosh/src/objects.c
--- nethack-3.4.3/src/objects.c	2003-12-08 10:39:13.000000000 +1100
+++ nethack-cosh/src/objects.c	2007-05-18 15:51:57.000000000 +1000
@@ -227,17 +227,19 @@
 	0, 0, 1,  4,100,  8,  8,  6, 0, B|P, P_POLEARMS, IRON, HI_METAL),
 
 /* bludgeons */
+WEAPON("cosh", (char *)0,
+        1, 0, 0, 6,  10,  2,  1,  1, 0, B,   P_CLUB, WOOD, HI_WOOD),
 WEAPON("mace", (char *)0,
 	1, 0, 0, 40, 30,  5,  6,  6, 0, B,   P_MACE, IRON, HI_METAL),
 						/* +1 small */
 WEAPON("morning star", (char *)0,
-	1, 0, 0, 12,120, 10,  4,  6, 0, B,   P_MORNING_STAR, IRON, HI_METAL),
+	1, 0, 0, 10,120, 10,  4,  6, 0, B,   P_MORNING_STAR, IRON, HI_METAL),
 						/* +d4 small, +1 large */
 WEAPON("war hammer", (char *)0,
-	1, 0, 0, 15, 50,  5,  4,  4, 0, B,   P_HAMMER, IRON, HI_METAL),
+	1, 0, 0, 13, 50,  5,  4,  4, 0, B,   P_HAMMER, IRON, HI_METAL),
 						/* +1 small */
 WEAPON("club", (char *)0,
-	1, 0, 0, 12, 30,  3,  6,  3, 0, B,   P_CLUB, WOOD, HI_WOOD),
+	1, 0, 0, 10, 30,  3,  6,  3, 0, B,   P_CLUB, WOOD, HI_WOOD),
 #ifdef KOPS
 WEAPON("rubber hose", (char *)0,
 	1, 0, 0,  0, 20,  3,  4,  3, 0, B,   P_WHIP, PLASTIC, CLR_BROWN),
diff -Nbaur nethack-3.4.3/src/u_init.c nethack-cosh/src/u_init.c
--- nethack-3.4.3/src/u_init.c	2003-12-08 10:39:13.000000000 +1100
+++ nethack-cosh/src/u_init.c	2007-05-21 13:42:25.000000000 +1000
@@ -175,6 +175,10 @@
  *	Optional extra inventory items.
  */
 
+static struct trobj Cosh[] = {
+	{ COSH, 0, WEAPON_CLASS, 1, 0 },
+        { 0, 0, 0, 0, 0 }
+};
 static struct trobj Tinopener[] = {
 	{ TIN_OPENER, 0, TOOL_CLASS, 1, 0 },
 	{ 0, 0, 0, 0, 0 }
@@ -689,6 +693,7 @@
 #endif
 		ini_inv(Rogue);
 		if(!rn2(5)) ini_inv(Blindfold);
+		if(!rn2(3)) ini_inv(Cosh);
 		knows_object(SACK);
 		skill_init(Skill_R);
 		break;
diff -Nbaur nethack-3.4.3/src/uhitm.c nethack-cosh/src/uhitm.c
--- nethack-3.4.3/src/uhitm.c	2003-12-08 10:39:13.000000000 +1100
+++ nethack-cosh/src/uhitm.c	2007-05-21 13:37:50.000000000 +1000
@@ -600,12 +600,47 @@
 		} else {
 		    tmp = dmgval(obj, mon);
 		    /* a minimal hit doesn't exercise proficiency */
-		    valid_weapon_attack = (tmp > 1);
+		    /* except for the cosh, which only does mininal hits */
+		    valid_weapon_attack = (tmp > 1) || (obj->otyp == COSH);
+
+		    /* MRKR: this is necessary to make the backstab 
+		     * check below work. Otherwise, if the player 
+		     * is faster than the monster, they can get backstabs
+		     * in just by moving in between strikes.
+		     */
+		    set_apparxy(mon);
+
 		    if (!valid_weapon_attack || mon == u.ustuck || u.twoweap) {
 			;	/* no special bonuses */
-		    } else if (mon->mflee && Role_if(PM_ROGUE) && !Upolyd) {
+		    } else if (Stealth && haseyes(mon->data) &&
+			(mon->mux != u.ux || mon->muy != u.uy)) {
+                    	 
 			You("strike %s from behind!", mon_nam(mon));
+			if (Role_if(PM_KNIGHT) && u.ualign.type == A_LAWFUL) {
+				You("scoundrel!");
+				adjalign(-1);
+			}
+
+			if (obj->otyp == COSH && mon->mcanmove) {
+			    int r = rn2(6) - obj->spe;
+		  	    if (r >= P_SKILL(P_CLUB) || obj->spe < 0) {	
+				pline("%s %s for a moment.", 
+				    Monnam(mon),
+       		            	    makeplural(stagger(mon->data, "stagger")));
+                		mon->mstun = 1;
+			    }
+			    else {
+				int amt = d(1 + obj->spe , 12);
+				pline("%s %s unconcious.",
+				    Monnam(mon),
+			 	    makeplural(stagger(mon->data, "fall")));
+				mon->mcanmove = 0;
+				mon->mfrozen = min(amt, 127);
+			    }
+			}
+			else {
 			tmp += rnd(u.ulevel);
+			}
 			hittxt = TRUE;
 		    } else if (dieroll == 2 && obj == uwep &&
 			  obj->oclass == WEAPON_CLASS &&