diff --git a/packages/tui/src/keys.ts b/packages/tui/src/keys.ts
index c26d0c17..6d4d14e1 100644
--- a/packages/tui/src/keys.ts
+++ b/packages/tui/src/keys.ts
@@ -642,9 +642,26 @@ function matchesModifyOtherKeys(data: string, expectedKeycode: number, expectedM
 // Generic Key Matching
 // =============================================================================
 
-function rawCtrlChar(letter: string): string {
-	const code = letter.toLowerCase().charCodeAt(0) - 96;
-	return String.fromCharCode(code);
+/**
+ * Get the control character for a key.
+ * Uses the universal formula: code & 0x1f (mask to lower 5 bits)
+ *
+ * Works for:
+ * - Letters a-z → 1-26
+ * - Symbols [\]_ → 27, 28, 29, 31
+ * - Also maps - to same as _ (same physical key on US keyboards)
+ */
+function rawCtrlChar(key: string): string | null {
+	const char = key.toLowerCase();
+	const code = char.charCodeAt(0);
+	if ((code >= 97 && code <= 122) || char === "[" || char === "\\" || char === "]" || char === "_") {
+		return String.fromCharCode(code & 0x1f);
+	}
+	// Handle - as _ (same physical key on US keyboards)
+	if (char === "-") {
+		return String.fromCharCode(31); // Same as Ctrl+_
+	}
+	return null;
 }
 
 function parseKeyId(keyId: string): { key: string; ctrl: boolean; shift: boolean; alt: boolean } | null {
@@ -966,9 +983,11 @@ export function matchesKey(data: string, keyId: KeyId): boolean {
 	// Handle single letter keys (a-z) and some symbols
 	if (key.length === 1 && ((key >= "a" && key <= "z") || SYMBOL_KEYS.has(key))) {
 		const codepoint = key.charCodeAt(0);
+		const rawCtrl = rawCtrlChar(key);
 
-		if (ctrl && alt && !shift && !_kittyProtocolActive && key >= "a" && key <= "z") {
-			return data === `\x1b${rawCtrlChar(key)}`;
+		if (ctrl && alt && !shift && !_kittyProtocolActive && rawCtrl) {
+			// Legacy: ctrl+alt+key is ESC followed by the control character
+			return data === `\x1b${rawCtrl}`;
 		}
 
 		if (alt && !ctrl && !shift && !_kittyProtocolActive && key >= "a" && key <= "z") {
@@ -977,9 +996,8 @@ export function matchesKey(data: string, keyId: KeyId): boolean {
 		}
 
 		if (ctrl && !shift && !alt) {
-			const raw = rawCtrlChar(key);
-			if (data === raw) return true;
-			if (data.length > 0 && data.charCodeAt(0) === raw.charCodeAt(0)) return true;
+			// Legacy: ctrl+key sends the control character
+			if (rawCtrl && data === rawCtrl) return true;
 			return matchesKittySequence(data, codepoint, MODIFIERS.ctrl);
 		}
 
@@ -1062,6 +1080,13 @@ export function parseKey(data: string): string | undefined {
 
 	// Legacy sequences (used when Kitty protocol is not active, or for unambiguous sequences)
 	if (data === "\x1b") return "escape";
+	if (data === "\x1c") return "ctrl+\\";
+	if (data === "\x1d") return "ctrl+]";
+	if (data === "\x1f") return "ctrl+-";
+	if (data === "\x1b\x1b") return "ctrl+alt+[";
+	if (data === "\x1b\x1c") return "ctrl+alt+\\";
+	if (data === "\x1b\x1d") return "ctrl+alt+]";
+	if (data === "\x1b\x1f") return "ctrl+alt+-";
 	if (data === "\t") return "tab";
 	if (data === "\r" || (!_kittyProtocolActive && data === "\n") || data === "\x1bOM") return "enter";
 	if (data === "\x00") return "ctrl+space";
diff --git a/packages/tui/test/keys.test.ts b/packages/tui/test/keys.test.ts
index ec7ce1d9..276cba7b 100644
--- a/packages/tui/test/keys.test.ts
+++ b/packages/tui/test/keys.test.ts
@@ -137,6 +137,39 @@ describe("matchesKey", () => {
 			assert.strictEqual(parseKey("\x00"), "ctrl+space");
 		});
 
+		it("should match legacy Ctrl+symbol", () => {
+			setKittyProtocolActive(false);
+			// Ctrl+\ sends ASCII 28 (File Separator) in legacy terminals
+			assert.strictEqual(matchesKey("\x1c", "ctrl+\\"), true);
+			assert.strictEqual(parseKey("\x1c"), "ctrl+\\");
+			// Ctrl+] sends ASCII 29 (Group Separator) in legacy terminals
+			assert.strictEqual(matchesKey("\x1d", "ctrl+]"), true);
+			assert.strictEqual(parseKey("\x1d"), "ctrl+]");
+			// Ctrl+_ sends ASCII 31 (Unit Separator) in legacy terminals
+			// Ctrl+- is on the same physical key on US keyboards
+			assert.strictEqual(matchesKey("\x1f", "ctrl+_"), true);
+			assert.strictEqual(matchesKey("\x1f", "ctrl+-"), true);
+			assert.strictEqual(parseKey("\x1f"), "ctrl+-");
+		});
+
+		it("should match legacy Ctrl+Alt+symbol", () => {
+			setKittyProtocolActive(false);
+			// Ctrl+Alt+[ sends ESC followed by ESC (Ctrl+[ = ESC)
+			assert.strictEqual(matchesKey("\x1b\x1b", "ctrl+alt+["), true);
+			assert.strictEqual(parseKey("\x1b\x1b"), "ctrl+alt+[");
+			// Ctrl+Alt+\ sends ESC followed by ASCII 28
+			assert.strictEqual(matchesKey("\x1b\x1c", "ctrl+alt+\\"), true);
+			assert.strictEqual(parseKey("\x1b\x1c"), "ctrl+alt+\\");
+			// Ctrl+Alt+] sends ESC followed by ASCII 29
+			assert.strictEqual(matchesKey("\x1b\x1d", "ctrl+alt+]"), true);
+			assert.strictEqual(parseKey("\x1b\x1d"), "ctrl+alt+]");
+			// Ctrl+_ sends ASCII 31 (Unit Separator) in legacy terminals
+			// Ctrl+- is on the same physical key on US keyboards
+			assert.strictEqual(matchesKey("\x1b\x1f", "ctrl+alt+_"), true);
+			assert.strictEqual(matchesKey("\x1b\x1f", "ctrl+alt+-"), true);
+			assert.strictEqual(parseKey("\x1b\x1f"), "ctrl+alt+-");
+		});
+
 		it("should parse legacy alt-prefixed sequences when kitty inactive", () => {
 			setKittyProtocolActive(false);
 			assert.strictEqual(matchesKey("\x1b ", "alt+space"), true);