diff --git a/include/decl.h b/include/decl.h
index 834b14ab8..711ba614e 100644
--- a/include/decl.h
+++ b/include/decl.h
@@ -462,6 +462,10 @@ struct ptr_array {
 };
 typedef struct ptr_array ptr_array_t;
 
+/* logging verbosity levels */
+#define LOG_MINIMAL 0
+#define LOG_VERBOSE 1
+
 #undef E
 
 #endif /* DECL_H */
diff --git a/include/extern.h b/include/extern.h
index d2ed2ff9e..3c74bfda0 100644
--- a/include/extern.h
+++ b/include/extern.h
@@ -27,6 +27,13 @@ E void NDECL(newgame);
 E void FDECL(welcome, (BOOLEAN_P));
 E time_t NDECL(get_realtime);
 E int FDECL(argcheck, (int, char **, enum earlyarg));
+E void NDECL(fuzzer_start);
+E void NDECL(fuzzer_stop);
+E void NDECL(fuzzer_toggle);
+E void VDECL(fuzzer_log, (int, const char *, ...)) PRINTF_F(2, 3);
+E void NDECL(fuzzer_check);
+E void NDECL(fuzzer_auto_start);
+E boolean FDECL(fuzzer_msg_history, (const char *));
 
 /* ### apply.c ### */
 
@@ -950,6 +957,7 @@ E boolean
 FDECL(fuzzymatch, (const char *, const char *, const char *, BOOLEAN_P));
 E void FDECL(init_random, (int FDECL((*fn), (int))));
 E void FDECL(reseed_random, (int FDECL((*fn), (int))));
+E void FDECL(set_random, (unsigned long, int FDECL((*fn), (int))));
 E time_t NDECL(getnow);
 E int NDECL(getyear);
 #if 0
@@ -2161,6 +2169,7 @@ E int FDECL(rnd, (int));
 E int FDECL(d, (int, int));
 E int FDECL(rne, (int));
 E int FDECL(rnz, (int));
+E unsigned long NDECL(rul);
 
 /* ### role.c ### */
 
diff --git a/include/flag.h b/include/flag.h
index 3ea3ada26..50f76c457 100644
--- a/include/flag.h
+++ b/include/flag.h
@@ -447,6 +447,10 @@ struct instance_flags {
                                     chosen_windowport[], but do not switch to
                                     it in the midst of options processing */
     boolean obsolete;  /* obsolete options can point at this, it isn't used */
+    boolean fuzzer_auto_start; /* start fuzzer automatically */
+    int fuzzer_stop_and_save;  /* move when fuzzer stops and saves game */
+    boolean fuzzer_saving;     /* fuzzer is saving game */
+    int verbose_logging_start; /* move when verbose fuzzer logging starts */
 };
 
 /*
diff --git a/src/allmain.c b/src/allmain.c
index 082447b3b..cde2ef9a2 100644
--- a/src/allmain.c
+++ b/src/allmain.c
@@ -436,6 +436,8 @@ boolean resuming;
 #ifdef MAIL
             ckmailstatus();
 #endif
+            fuzzer_check();
+
             rhack((char *) 0);
         }
         if (u.utotype)       /* change dungeon level */
@@ -583,6 +585,8 @@ newgame()
 {
     int i;
 
+    fuzzer_auto_start();
+
 #ifdef MFLOPPY
     gameDiskPrompt();
 #endif
@@ -922,4 +926,131 @@ const char *opts;
 #endif
     return;
 }
+
+static FILE * g_fuzzer_log_file = NULL;
+static int g_fuzzer_log_level = LOG_MINIMAL;
+
+/* fuzzer_start() starts the fuzzer opening the fuzzer log file */
+void
+fuzzer_start()
+{
+    if (!iflags.debug_fuzzer) {
+        const char * fq_replay;
+
+        iflags.debug_fuzzer = TRUE;
+        iflags.fuzzer_auto_start = FALSE;
+
+        nhassert(g_fuzzer_log_file == NULL);
+        fq_replay = fqname("fuzzer.log", SAVEPREFIX, 0);
+
+        g_fuzzer_log_file = fopen(fq_replay, "w");
+    }
+}
+
+/* fuzzer_stop() stops the fuzzer and close the fuzzer log file */
+void
+fuzzer_stop()
+{
+    if (iflags.debug_fuzzer) {
+        if(g_fuzzer_log_file != NULL) {
+            fclose(g_fuzzer_log_file);
+            g_fuzzer_log_file = NULL;
+        }
+    }
+}
+
+/* fuzzer_toggle() toggles fuzzer state */
+void
+fuzzer_toggle()
+{
+    if (iflags.debug_fuzzer)
+        fuzzer_stop();
+    else
+        fuzzer_start();
+}
+
+/* fuzzer_log() is used to place messages in the file 'fuzzer.log'.  This
+ * log is the primary tool for monitoring fuzzer activity and tracking down
+ * issues that the fuzzer is able to reproduce.
+ */
+void
+fuzzer_log
+VA_DECL2(int, level, const char *, str)
+{
+    VA_START(str);
+    VA_INIT(str, char *);
+
+    if (!g_fuzzer_log_file)
+        return;
+
+    if (iflags.verbose_logging_start != 0 && moves >= iflags.verbose_logging_start)
+        g_fuzzer_log_level = LOG_VERBOSE;
+
+    if (level <= g_fuzzer_log_level)
+        Vfprintf(g_fuzzer_log_file, str, VA_ARGS);
+
+    VA_END();
+}
+
+/* fuzzer_check() is called prior to rhack(0) to allow the fuzzer to
+ * check if it should stop and to allow it to reseed the game.
+ */
+void
+fuzzer_check()
+{
+    if (iflags.debug_fuzzer)
+    {
+        if (moves >= iflags.fuzzer_stop_and_save) {
+            iflags.fuzzer_saving = TRUE;
+            dosave0();
+            exit_nhwindows("Goodbye from the fuzzer...");
+            fuzzer_stop();
+            nh_terminate(EXIT_SUCCESS);
+        }
+
+        unsigned long seed = rul();
+        set_random(seed, rn2);
+        fuzzer_log(LOG_MINIMAL, "SEED:%ld:%lu\n", moves, seed);
+
+    }
+}
+
+/* fuzzer_auto_start is called when creating a new game to allow
+ * the fuzzer to start itself.
+ */
+void
+fuzzer_auto_start()
+{
+    if (iflags.fuzzer_auto_start) {
+        nhassert(!iflags.debug_fuzzer);
+        fuzzer_start();
+        unsigned long seed = rul();
+        set_random(seed, rn2);
+        fuzzer_log(LOG_MINIMAL, "START:%ld:%lu\n", moves, seed);
+    }
+}
+
+/* fuzzer_msg_history is called during save file recovery to allow
+ * the fuzzer to snoop the messages being recovered.  The fuzzer
+ * saves a seed as a message in save files and this is the mechanism
+ * used to recover that seed if the fuzzer is being auto started.
+ */
+boolean
+fuzzer_msg_history(msg)
+    const char * msg;
+{
+    long saved_moves;
+    unsigned long saved_seed;
+    if (sscanf(msg, "SEED:%ld:%lu", &saved_moves, &saved_seed) == 2) {
+        nhassert(saved_moves == moves);
+        if (iflags.fuzzer_auto_start) {
+            fuzzer_start();
+            set_random(saved_seed, rn2);
+            fuzzer_log(LOG_MINIMAL, "START:%ld:%lu\n", moves, saved_seed);
+        }
+        return TRUE;
+    }
+
+    return FALSE;
+}
 /*allmain.c*/
diff --git a/src/hacklib.c b/src/hacklib.c
index 9fe316517..1f43325df 100644
--- a/src/hacklib.c
+++ b/src/hacklib.c
@@ -854,7 +854,7 @@ STATIC_DCL struct tm *NDECL(getlt);
 /* Sets the seed for the random number generator */
 #ifdef USE_ISAAC64
 
-static void
+void
 set_random(seed, fn)
 unsigned long seed;
 int FDECL((*fn), (int));
@@ -865,7 +865,7 @@ int FDECL((*fn), (int));
 #else /* USE_ISAAC64 */
 
 /*ARGSUSED*/
-static void
+void
 set_random(seed, fn)
 unsigned long seed;
 int FDECL((*fn), (int)) UNUSED;
@@ -917,7 +917,7 @@ int FDECL((*fn), (int));
 {
    /* only reseed if we are certain that the seed generation is unguessable
     * by the players. */
-    if (has_strong_rngseed)
+    if (has_strong_rngseed && !iflags.debug_fuzzer)
         init_random(fn);
 }
 
@@ -1108,6 +1108,9 @@ phase_of_the_moon() /* 0-7, with 0: new, 4: full */
     register struct tm *lt = getlt();
     register int epact, diy, goldn;
 
+    if(iflags.debug_fuzzer)
+        return rn2(8);
+
     diy = lt->tm_yday;
     goldn = (lt->tm_year % 19) + 1;
     epact = (11 * goldn + 18) % 30;
@@ -1122,6 +1125,9 @@ friday_13th()
 {
     register struct tm *lt = getlt();
 
+    if(iflags.debug_fuzzer)
+        return rn2(30);
+
     /* tm_wday (day of week; 0==Sunday) == 5 => Friday */
     return (boolean) (lt->tm_wday == 5 && lt->tm_mday == 13);
 }
diff --git a/src/restore.c b/src/restore.c
index b6126a227..7d1f6d894 100644
--- a/src/restore.c
+++ b/src/restore.c
@@ -1231,6 +1231,8 @@ register int fd;
             panic("restore_msghistory: msg too big (%d)", msgsize);
         mread(fd, (genericptr_t) msg, msgsize);
         msg[msgsize] = '\0';
+        if(fuzzer_msg_history(msg))
+            continue;
         putmsghistory(msg, TRUE);
         ++msgcount;
     }
diff --git a/src/rnd.c b/src/rnd.c
index 0ca649fbb..5473be949 100644
--- a/src/rnd.c
+++ b/src/rnd.c
@@ -56,10 +56,21 @@ int FDECL((*fn), (int));
                  (int) sizeof seed);
 }
 
+unsigned long
+rul()
+{
+    unsigned long value;
+
+    value = (unsigned long) isaac64_next_uint64(&rnglist[CORE].rng_state);
+    fuzzer_log(LOG_VERBOSE, "RANDOM:%llu\n", value);
+
+    return value;
+}
+
 static int
 RND(int x)
 {
-    return (isaac64_next_uint64(&rnglist[CORE].rng_state) % x);
+    return (rul() % x);
 }
 
 /* 0 <= rn2(x) < x, but on a different sequence from the "main" rn2;
@@ -69,6 +80,8 @@ int
 rn2_on_display_rng(x)
 register int x;
 {
+    if (iflags.debug_fuzzer)
+        return rn2(x);
     return (isaac64_next_uint64(&rnglist[DISP].rng_state) % x);
 }
 
@@ -94,6 +107,20 @@ register int x;
     seed *= 2739110765;
     return (int)((seed >> 16) % (unsigned)x);
 }
+
+unsigned long
+rul()
+{
+#if defined(LINT) && defined(UNIX)
+    return (unsigned long) rand();
+#else /* LINT */
+#if defined(UNIX) || defined(RANDOM)
+    return (unsigned long) Rand();
+#else
+    return (unsigned long) (Rand() >> 3);
+#endif /* defined(UNIX) || defined(RANDOM) */
+#endif /* LINT */
+}
 #endif  /* USE_ISAAC64 */
 
 /* 0 <= rn2(x) < x */
diff --git a/src/save.c b/src/save.c
index e0af4b8d2..e931eae76 100644
--- a/src/save.c
+++ b/src/save.c
@@ -139,7 +139,7 @@ dosave0()
         return 0;
 #endif
 
-    HUP if (iflags.window_inited) {
+    HUP if (!iflags.debug_fuzzer && iflags.window_inited) {
         nh_uncompress(fq_save);
         fd = open_savefile();
         if (fd > 0) {
@@ -1238,6 +1238,18 @@ int fd, mode;
             bwrite(fd, (genericptr_t) msg, msglen);
             ++msgcount;
         }
+        /* If the fuzzer is stopping and saving, save a seed as a message.
+           In 3.7, we will modify the save file format and save the seed
+           directly in the saved game state. */
+        if (iflags.fuzzer_saving) {
+            char message[BUFSIZ];
+            unsigned long seed = rul();
+            sprintf(message, "SEED:%ld:%lu", moves, seed);
+            fuzzer_log(LOG_MINIMAL, "STOP:%ld:%lu\n", moves, seed);
+            msglen = strlen(message);
+            bwrite(fd, (genericptr_t) &msglen, sizeof msglen);
+            bwrite(fd, (genericptr_t) message, msglen);
+        }
         bwrite(fd, (genericptr_t) &minusone, sizeof (int));
     }
     debugpline1("Stored %d messages into savefile.", msgcount);
diff --git a/sys/winnt/nttty.c b/sys/winnt/nttty.c
index a8000bc05..4cca4dcbd 100644
--- a/sys/winnt/nttty.c
+++ b/sys/winnt/nttty.c
@@ -475,8 +475,14 @@ int *x, *y, *mod;
     coord cc;
     DWORD count;
     really_move_cursor();
-    if (iflags.debug_fuzzer)
-        return randomkey();
+    if (iflags.debug_fuzzer) {
+        int poskey = randomkey();
+        if (poskey == 0) {
+            *x = rn2(console.width);
+            *y = rn2(console.height);
+        }
+        return poskey;
+    }
     ch = (program_state.done_hup)
              ? '\033'
              : keyboard_handler.pCheckInput(
diff --git a/sys/winnt/windmain.c b/sys/winnt/windmain.c
index b2bb18e79..d1712ffe4 100644
--- a/sys/winnt/windmain.c
+++ b/sys/winnt/windmain.c
@@ -336,7 +336,7 @@ attempt_restore:
             resuming = TRUE; /* not starting new game */
             if (discover)
                 You("are in non-scoring discovery mode.");
-            if (discover || wizard) {
+            if ((discover || wizard) && !iflags.fuzzer_auto_start) {
                 if (yn("Do you want to keep the save file?") == 'n')
                     (void) delete_savefile();
                 else {
@@ -461,6 +461,23 @@ char *argv[];
         case 'X':
             discover = TRUE, wizard = FALSE;
             break;
+        case 'F':
+            {
+                iflags.fuzzer_auto_start = 1;
+
+                if (argc > 1 && argv[1][0] != '-') {
+                    argc--;
+                    argv++;
+                    iflags.fuzzer_stop_and_save = atoi(*argv);
+
+                    if (argc > 1 && argv[1][0] != '-') {
+                        argc--;
+                        argv++;
+                        iflags.verbose_logging_start = atoi(*argv);
+                    }
+                }
+            }
+            break;
 #ifdef NEWS
         case 'n':
             iflags.news = FALSE;
diff --git a/win/win32/scripts/fuzzer/clean.bat b/win/win32/scripts/fuzzer/clean.bat
new file mode 100644
index 000000000..a02c48739
--- /dev/null
+++ b/win/win32/scripts/fuzzer/clean.bat
@@ -0,0 +1,8 @@
+set BIN_DIR=..\..\..\..\bin\Debug\Win32
+
+set FUZZER_LOG=%BIN_DIR%\fuzzer.log
+set FUZZER_DIR=%BIN_DIR%\fuzzer
+
+if exist %BIN_DIR%\%USERNAME%* del %BIN_DIR%\%USERNAME%*
+if exist %FUZZER_LOG% del %FUZZER_LOG%
+
diff --git a/win/win32/scripts/fuzzer/longtest.bat b/win/win32/scripts/fuzzer/longtest.bat
new file mode 100644
index 000000000..e5e8d1529
--- /dev/null
+++ b/win/win32/scripts/fuzzer/longtest.bat
@@ -0,0 +1,23 @@
+echo off
+
+SETLOCAL ENABLEEXTENSIONS
+SETLOCAL ENABLEDELAYEDEXPANSION
+
+set STEP_SIZE=5000
+set FINAL_MOVE=500000
+set START_MOVE=5000
+
+for /L %%i in (%START_MOVE%, %STEP_SIZE%, %FINAL_MOVE%) do (
+
+    call runtill.bat %%i
+	
+	if ERRORLEVEL 1 (
+	    echo FAILED getting running to %%i.
+		exit /b 1
+	)
+
+)
+
+echo SUCCESS.
+
+
diff --git a/win/win32/scripts/fuzzer/restore.bat b/win/win32/scripts/fuzzer/restore.bat
new file mode 100644
index 000000000..9752fed96
--- /dev/null
+++ b/win/win32/scripts/fuzzer/restore.bat
@@ -0,0 +1,7 @@
+call clean.bat
+
+set BIN_DIR=..\..\..\..\bin\Debug\Win32
+set SAVED_GAME=%USERNAME%-wizard.NetHack-saved-game
+set FUZZER_DIR=%BIN_DIR%\fuzzer
+
+copy %FUZZER_DIR%\%SAVED_GAME% %BIN_DIR%\%SAVED_GAME%
diff --git a/win/win32/scripts/fuzzer/runtill.bat b/win/win32/scripts/fuzzer/runtill.bat
new file mode 100644
index 000000000..ebb5aa4b6
--- /dev/null
+++ b/win/win32/scripts/fuzzer/runtill.bat
@@ -0,0 +1,73 @@
+REM
+REM runtill target_move
+REM 
+echo off
+
+SETLOCAL ENABLEEXTENSIONS
+SETLOCAL ENABLEDELAYEDEXPANSION
+
+set TARGET_MOVE=%1
+
+if %TARGET_MOVE% == "" (
+  echo Usage:runtill target_move
+  goto :eof
+)
+
+set BIN_DIR=..\..\..\..\bin\Debug\Win32
+set SAVED_GAME=%USERNAME%-wizard.NetHack-saved-game
+set LOG_FILE=%BIN_DIR%\runtil.log
+set FUZZER_LOG=%BIN_DIR%\fuzzer.log
+set FUZZER_DIR=%BIN_DIR%\fuzzer
+set BASELINE=%FUZZER_DIR%\fuzzer.log
+
+if not exist %FUZZER_DIR% mkdir %FUZZER_DIR%
+
+call clean.bat
+
+if not exist %FUZZER_DIR%\%SAVED_GAME% (
+	%BIN_DIR%\nethack -D -F 0
+
+	copy %BIN_DIR%\%SAVED_GAME% %FUZZER_DIR%
+)
+
+call restore.bat
+
+%BIN_DIR%\nethack -D -F %TARGET_MOVE%
+
+move %BIN_DIR%\*.snap %BIN_DIR%\snapshots
+copy %FUZZER_LOG% %BASELINE%
+
+for /f "tokens=2,3 delims=: usebackq" %%i in (`findstr /c:START %BASELINE%`) do (
+	set START_SEED=%%j
+	set START_MOVE=%%i
+)
+
+for /f "tokens=2,3 delims=: usebackq" %%i in (`findstr /c:STOP %BASELINE%`) do (
+	set STOP_SEED=%%j
+	set STOP_MOVE=%%i
+)
+
+if !STOP_MOVE! LSS %TARGET_MOVE% (
+	cls
+	echo FAILED: Failed to reach target move. !STOP_MOVE! is not GTE %TARGET_MOVE%.
+	exit /b 1
+)
+
+call restore.bat
+
+%BIN_DIR%\nethack -D -F %TARGET_MOVE%
+
+fc %FUZZER_LOG% %BASELINE%
+  
+if ERRORLEVEL 1 (
+	cls
+	echo FAILED: Unable to reproduce same timeline
+	exit /b 1
+)
+
+del /q %FUZZER_DIR%\%SAVED_GAME%
+
+copy %BIN_DIR%\%SAVED_GAME% %FUZZER_DIR%
+
+echo !START_MOVE! to !STOP_MOVE!.
+echo SUCCESS.