diff --git a/scripts/unicode.py b/scripts/unicode.py
index 4879e82..9f757eb 100755
--- a/scripts/unicode.py
+++ b/scripts/unicode.py
@@ -545,6 +545,12 @@ def load_zero_widths() -> list[bool]:
         lambda cp: operator.setitem(zw_map, cp, True),
     )
 
+    # HALFWIDTH KATAKANA VOICED SOUND MARK and HALFWIDTH KATAKANA SEMI-VOICED SOUND MARK
+    # are `Lm` letters even though they currently carry `Grapheme_Extend`.
+    # They occupy their own cell in terminal-style width calculations.
+    zw_map[0xFF9E] = False
+    zw_map[0xFF9F] = False
+
     # Treat `Hangul_Syllable_Type`s of `Vowel_Jamo` and `Trailing_Jamo`
     # as zero-width. This matches the behavior of glibc `wcwidth`.
     #
diff --git a/src/gen/tables.rs b/src/gen/tables.rs
index c8d3e62..b46ba39 100644
--- a/src/gen/tables.rs
+++ b/src/gen/tables.rs
@@ -616,7 +616,7 @@ pub(crate) static WIDTH_LEAVES: Align32<[[u8; 32]; WIDTH_LEAVES_LEN]> = Align32(
         0x55, 0x55,
     ],
     [
-        0x55, 0x55, 0x55, 0x55, 0x55, 0x55, 0x55, 0x05, 0x54, 0x55, 0x55, 0x55, 0x55, 0x55, 0x55,
+        0x55, 0x55, 0x55, 0x55, 0x55, 0x55, 0x55, 0x55, 0x54, 0x55, 0x55, 0x55, 0x55, 0x55, 0x55,
         0x55, 0x55, 0x55, 0x55, 0x55, 0x55, 0x55, 0x55, 0x55, 0xAA, 0x6A, 0x55, 0x55, 0x00, 0x00,
         0x54, 0x55,
     ],
@@ -1157,7 +1157,7 @@ pub(crate) static WIDTH_LEAVES: Align32<[[u8; 32]; WIDTH_LEAVES_LEN]> = Align32(
     ],
     #[cfg(feature = "cjk")]
     [
-        0x55, 0x55, 0x55, 0x55, 0x55, 0x55, 0x55, 0x05, 0x54, 0x55, 0x55, 0x55, 0x55, 0x55, 0x55,
+        0x55, 0x55, 0x55, 0x55, 0x55, 0x55, 0x55, 0x55, 0x54, 0x55, 0x55, 0x55, 0x55, 0x55, 0x55,
         0x55, 0x55, 0x55, 0x55, 0x55, 0x55, 0x55, 0x55, 0x55, 0xAA, 0x6A, 0x55, 0x55, 0x00, 0x00,
         0x54, 0x59,
     ],
@@ -1217,7 +1217,7 @@ pub(crate) static NON_TRANSPARENT_ZERO_WIDTHS: [([u8; 3], [u8; 3]); 71] = [
     ([0xC0, 0xA9, 0x00], [0xC0, 0xA9, 0x00]),
     ([0xB0, 0xD7, 0x00], [0xC6, 0xD7, 0x00]),
     ([0xCB, 0xD7, 0x00], [0xFB, 0xD7, 0x00]),
-    ([0x9E, 0xFF, 0x00], [0xA0, 0xFF, 0x00]),
+    ([0xA0, 0xFF, 0x00], [0xA0, 0xFF, 0x00]),
     ([0xF0, 0xFF, 0x00], [0xF8, 0xFF, 0x00]),
     ([0xC0, 0x11, 0x01], [0xC0, 0x11, 0x01]),
     ([0xC2, 0x11, 0x01], [0xC3, 0x11, 0x01]),
diff --git a/src/lib.rs b/src/lib.rs
index 6d8b38e..40b132a 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -98,7 +98,8 @@
 //!       - [Characters](https://util.unicode.org/UnicodeJsps/list-unicodeset.jsp?a=%5Cp%7BDefault_Ignorable_Code_Point%7D)
 //!         with the [`Default_Ignorable_Code_Point`] property.
 //!       - [Characters](https://util.unicode.org/UnicodeJsps/list-unicodeset.jsp?a=%5Cp%7BGrapheme_Extend%7D)
-//!         with the [`Grapheme_Extend`] property.
+//!         with the [`Grapheme_Extend`] property, except [`'\u{FF9E}'` HALFWIDTH KATAKANA VOICED SOUND MARK](https://util.unicode.org/UnicodeJsps/character.jsp?a=FF9E)
+//!         and [`'\u{FF9F}'` HALFWIDTH KATAKANA SEMI-VOICED SOUND MARK](https://util.unicode.org/UnicodeJsps/character.jsp?a=FF9F).
 //!       - [Characters](https://util.unicode.org/UnicodeJsps/list-unicodeset.jsp?a=%5Cp%7BHangul_Syllable_Type%3DV%7D%5Cp%7BHangul_Syllable_Type%3DT%7D)
 //!         with a [`Hangul_Syllable_Type`] of `Vowel_Jamo` (`V`) or `Trailing_Jamo` (`T`).
 //!       - The following [`Prepended_Concatenation_Mark`]s:
diff --git a/tests/tests.rs b/tests/tests.rs
index 7ca32a4..0f83c65 100644
--- a/tests/tests.rs
+++ b/tests/tests.rs
@@ -38,6 +38,11 @@ fn test_emoji() {
     assert_width!("👩‍🔬", 2, 2); // Woman scientist
 }
 
+#[test]
+fn test_halfwidth_katakana() {
+    assert_width!("ﾊﾟｸﾞ", 4, 4); // Halfwidth Katakana letters Pa, Gu (pug dog)
+}
+
 // From README
 #[test]
 fn test_bad_devanagari() {
@@ -63,6 +68,8 @@ fn test_char2() {
     assert_width!('\u{1160}', Some(0), Some(0));
     assert_width!('\u{a1}', Some(1), Some(2));
     assert_width!('\u{300}', Some(0), Some(0));
+    assert_width!('\u{FF9E}', Some(1), Some(1));
+    assert_width!('\u{FF9F}', Some(1), Some(1));
 }
 
 #[test]