diff --git a/README.md b/README.md
index a42efc9..2cf84c7 100644
--- a/README.md
+++ b/README.md
@@ -4,7 +4,7 @@ vim-lesser-align
 Yet another Vim alignment plugin without too much ambition.
 
 This plugin clearly has less features than the other pre-existing ones with the similar goals,
-but it is simpler, easier to use, and good enough for most of the cases.
+but it is simpler, easier to use, and good enough for the most of the cases.
 
 Usage
 -----
@@ -20,8 +20,8 @@ vnoremap <silent> <Enter> :LesserAlign<cr>
 Then a key sequence becomes a combination of 3 parts.
 
 1. `<Enter>`
-    - Shortcut for `:LesserAssign<Enter>`
-1. Integer (optional, default: 1)
+    - Shortcut for `:LesserAssign<cr>`
+1. Integer (*optional*, default: 1)
     - `1`: Alignment around 1st delimiter
     - `2`: Alignment around 2nd delimiter
     - `...`
@@ -36,16 +36,16 @@ Then a key sequence becomes a combination of 3 parts.
 Examples
 --------
 
-| Keystroke           | Description                                           |
-| ------------------- | ----------------------------------------------------- |
-| `<Enter>=`          | Alignment around 1st equals sign (and the likes)      |
-| `<Enter>2=`         | Alignment around 2nd equals sign (and the likes)      |
-| `<Enter>3=`         | Alignment around 3rd equals sign (and the likes)      |
-| `<Enter>*=`         | Alignment around all equals signs (and the likes)     |
-| `<Enter><space>`    | Alignment around 1st whitespace                       |
-| `<Enter>2<space>`   | Alignment around 2nd whitespace                       |
-| `<Enter>:`          | Alignment around 1st colon                            |
-| ...                 | ...                                                   |
+| With visual map   | Description                                        | Equivalent command      |
+| ----------------- | -------------------------------------------------- | ----------------------- |
+| `<Enter>=`        | Alignment around 1st equals sign (and the likes)   | `:'<,'>LesserAlign =`   |
+| `<Enter>2=`       | Alignment around 2nd equals sign (and the likes)   | `:'<,'>LesserAlign 2=`  |
+| `<Enter>3=`       | Alignment around 3rd equals sign (and the likes)   | `:'<,'>LesserAlign 3=`  |
+| `<Enter>*=`       | Alignment around all equals signs (and the likes)  | `:'<,'>LesserAlign *=`  |
+| `<Enter><space>`  | Alignment around 1st whitespace                    | `:'<,'>LesserAlign \ `  |
+| `<Enter>2<space>` | Alignment around 2nd whitespace                    | `:'<,'>LesserAlign 2\ ` |
+| `<Enter>:`        | Alignment around 1st colon                         | `:'<,'>LesserAlign :`   |
+| ...               | ...                                                |                         |
 
 Defining custom alignment rules
 -------------------------------
diff --git a/autoload/lesser_align.vim b/autoload/lesser_align.vim
index 38b07ca..09cf5a8 100644
--- a/autoload/lesser_align.vim
+++ b/autoload/lesser_align.vim
@@ -78,38 +78,61 @@ function! s:do_align(fl, ll, pattern, nth, ml, mr, stick_to_left, recursive)
   endif
 endfunction
 
-function! lesser_align#align() range
-  echon "\rlesser-align ()"
-  let n = ''
+function! lesser_align#align(...) range
   let recursive = 0
+  let n         = ''
+  let ch        = ''
 
-  while 1
-    let c  = getchar()
-    let ch = nr2char(c)
-    if c == 3 || c == 27
+  if a:0 == 0
+    echon "\rlesser-align ()"
+    while 1
+      let c  = getchar()
+      let ch = nr2char(c)
+      if c == 3 || c == 27
+        return
+      elseif c >= 48 && c <= 57
+        if n == '*'
+          echon "\rField number(*) already specified"
+          return
+        endif
+        let n = n . nr2char(c)
+        echon "\rlesser-align (". n .")"
+      elseif ch == '*'
+        if !empty(n)
+          echon "\rField number(". n .") already specified"
+          return
+        endif
+        let n = '*'
+        echon "\rlesser-align (*)"
+      else
+        break
+      endif
+    endwhile
+  elseif a:0 == 1
+    let tokens = matchlist(a:1, '^\([1-9][0-9]*\|\*\)\?\(.\)$')
+    if empty(tokens)
+      echo "Invalid arguments: ". a:1
       return
-    elseif c >= 48 && c <= 57
-      if recursive
-        echo "Number(*) already specified"
-        return
-      endif
-      let n = n . nr2char(c)
-      echon "\rlesser-align (". n .")"
-    elseif ch == '*'
-      if !empty(n)
-        echo "Number already specified"
-        return
-      endif
-      let recursive = 1
-      echon "\rlesser-align (*)"
-    else
-      break
     endif
-  endwhile
+    let [n, ch] = tokens[1:2]
+  elseif a:0 == 2
+    let n  = a:1
+    let ch = a:2
+  else
+    echo "Invalid number of arguments: ". a:0 ." (expected 0, 1, or 2)"
+    return
+  endif
 
-  let n = empty(n) ? 1 : n
+  if n == '*'
+    let n = 1
+    let recursive = 1
+  elseif empty(n)
+    let n = 1
+  elseif n != string(str2nr(n))
+    echon "\rInvalid field number: ". n
+    return
+  endif
 
-  let error = 0
   if has_key(g:lesser_align_delimiters_merged, ch)
     let dict = g:lesser_align_delimiters_merged[ch]
     call s:do_align(a:firstline, a:lastline,
@@ -118,14 +141,9 @@ function! lesser_align#align() range
                   \ get(dict, 'margin_left', ' '),
                   \ get(dict, 'margin_right', ' '),
                   \ get(dict, 'stick_to_left', 0), recursive)
-  else
-    let error = 1
-  endif
-
-  if error
-    echon "\rUnknown delimiter: ". ch
-  else
     echon "\rlesser-align (". (recursive ? '*' : n) . ch .")"
+  else
+    echon "\rUnknown delimiter: ". ch
   endif
 endfunction
 
diff --git a/plugin/lesser_align.vim b/plugin/lesser_align.vim
index 592352e..66b034e 100644
--- a/plugin/lesser_align.vim
+++ b/plugin/lesser_align.vim
@@ -3,4 +3,4 @@ if exists("g:lesser_align_plugin_loaded")
 endif
 let g:lesser_align_plugin_loaded = 1
 
-command! -nargs=0 -range LesserAlign <line1>,<line2>call lesser_align#align()
+command! -nargs=* -range LesserAlign <line1>,<line2>call lesser_align#align(<f-args>)