diff --git a/ChangeLog b/ChangeLog
index c9fc1e9b9..899c6d393 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,9 @@
+2020-09-08  Boruch Baum  <boruch_baum@gmx.com>
+
+	* w3m-ems.el (w3m-tab-move-right, w3m-tab-move-left): BUGFIX: moving
+	with prefix-arg > 1 was swapping tab positions instead of adjusting all
+	tab numbers in between.
+
 2020-09-03  Katsumi Yamaoka  <yamaoka@jpl.org>
 
 	Allow url like "file:foo.txt" (bug#969386 of debian)
diff --git a/w3m-ems.el b/w3m-ems.el
index 827062d33..21d0c3962 100644
--- a/w3m-ems.el
+++ b/w3m-ems.el
@@ -883,37 +883,59 @@ fast operation of mouse wheel."
 		     last-command-event))
   (w3m-tab-next-buffer (- (or n 1)) event))
 
-(defun w3m-tab-move-right (&optional n event)
+(defun w3m-tab-move-right (&optional mv-amt event)
   "Move the current tab right-ward (ie. next, higher number).
-Use the prefix argument to move the tab N positions right-ward.
+Use the prefix argument to move the tab MV-AMT positions right-ward.
 EVENT is an internal arg for mouse control."
   (interactive (list (prefix-numeric-value current-prefix-arg)
 		     last-command-event))
-  (unless n (setq n 1))
-  (when (and (/= n 0) (eq major-mode 'w3m-mode))
-    (let* ((buffers (if (> n 0)
-			(w3m-list-buffers)
-		      (setq n (- n))
-		      (nreverse (w3m-list-buffers))))
-	   (dest (or (nth n (memq (current-buffer) buffers))
-		     (car (last buffers))))
-	   (next (w3m-buffer-number dest))
-	   (cur (w3m-buffer-number (current-buffer))))
-      (rename-buffer "*w3m*<0>")
-      (w3m-buffer-set-number dest cur)
-      (w3m-buffer-set-number (current-buffer) next)
-      (w3m-select-buffer-update)
-      (w3m-tab-mouse-track-selected-tab event next t))))
+  (unless mv-amt (setq mv-amt 1))
+  (if (> 0 mv-amt)
+    (w3m-tab-move-left (- mv-amt) event)
+   (when (and (/= mv-amt 0) (eq major-mode 'w3m-mode))
+     (let* ((start-buf (current-buffer))
+            (start-num (w3m-buffer-number start-buf))
+            (buffers (w3m-list-buffers))
+            (len     (length buffers))
+            (this-num (1- start-num))
+            this-buf)
+       (setq mv-amt  (min mv-amt (- len start-num)))
+       (setq buffers (last buffers (- len start-num)))
+       (setq buffers (butlast buffers (- (length buffers) mv-amt)))
+       (rename-buffer "*w3m*<0>")
+       (while (setq this-buf (pop buffers))
+         (w3m-buffer-set-number this-buf (incf this-num)))
+       (w3m-buffer-set-number start-buf (+ start-num mv-amt))
+       (w3m-select-buffer-update)
+       (w3m-tab-mouse-track-selected-tab event (+ start-num mv-amt) t)))))
 
 (defalias 'w3m-tab-move-next 'w3m-tab-move-right)
 
-(defun w3m-tab-move-left (&optional n event)
+(defun w3m-tab-move-left (&optional mv-amt event)
   "Move the current tab left-ward (ie. prior, lower number).
-Use the prefix argument to move the tab N positions left-ward.
+Use the prefix argument to move the tab MV-AMT positions left-ward.
 EVENT is an internal arg for mouse control."
   (interactive (list (prefix-numeric-value current-prefix-arg)
-		     last-command-event))
-  (w3m-tab-move-right (- n) event))
+                     last-command-event))
+  (unless mv-amt (setq mv-amt 1))
+  (if (> 0 mv-amt)
+    (w3m-tab-move-right (- mv-amt) event)
+   (when (and (/= mv-amt 0) (eq major-mode 'w3m-mode))
+     (let* ((start-buf (current-buffer))
+            (start-num (w3m-buffer-number start-buf))
+            (buffers (nreverse (w3m-list-buffers)))
+            (len     (length buffers))
+            (this-num (1+ start-num))
+            this-buf)
+       (setq mv-amt  (min mv-amt start-num))
+       (setq buffers (last buffers (1- start-num)))
+       (setq buffers (butlast buffers (- (length buffers) mv-amt)))
+       (rename-buffer "*w3m*<0>")
+       (while (setq this-buf (pop buffers))
+         (w3m-buffer-set-number this-buf (decf this-num)))
+       (w3m-buffer-set-number start-buf (- start-num mv-amt))
+       (w3m-select-buffer-update)
+       (w3m-tab-mouse-track-selected-tab event (+ start-num mv-amt) t)))))
 
 (defalias 'w3m-tab-move-prior 'w3m-tab-move-left)