@@ -15,6 +15,7 @@ Open `index.html` in a browser, or serve the folder with any static file server.
 - **Words mode**: type a fixed 10, 25, or 50 words. The clock counts up.
 - **Categories**:
   - Common Words (the default): 200 frequent English words in random order, never the same word twice in a row. Settings can add punctuation (capitalized sentences, commas, full stops) and numbers.
+  - Weak Keys: common words that contain the three letters you miss most often, by miss rate, among letters you have typed at least five times. Until there is enough data it uses all common words.
   - Quotes: 50 passages, most of them opening lines of public-domain books.
   - Technology: 50 quotes about programming and computing.
   - Code Snippets: a mix of JavaScript, CSS, SQL, and shell lines.
@@ -28,7 +29,7 @@ Open `index.html` in a browser, or serve the folder with any static file server.
 - **Caps Lock warning**: a notice above the text while Caps Lock is on.
 - **Hard Mode**: blurs the characters you have already typed, so you cannot see your mistakes. The text ahead stays readable.
 - **Ghost Mode**: records the timing of your best run and replays its position as a second cursor while you type.
-- **Results**: a modal with your WPM and accuracy; raw WPM (all typed characters, right or wrong); correct and wrong character counts; elapsed time; whether the run set a new best for its settings, and the previous best; a line chart of WPM at the end of each second of the run; a line chart of your last ten runs at the current settings once you have two or more; and a Share button. The shared text has the WPM, accuracy, settings, and a link to the site. On touch devices it opens the system share sheet; elsewhere it copies to the clipboard.
+- **Results**: a modal with your WPM and accuracy; raw WPM (all typed characters, right or wrong); correct and wrong character counts; elapsed time; whether the run set a new best for its settings, and the previous best; the keys you missed most in this run; a line chart of WPM at the end of each second of the run; a line chart of your last ten runs at the current settings once you have two or more; a Share button; and, once you have missed letters often enough, a button that starts a Weak Keys run. The shared text has the WPM, accuracy, settings, and a link to the site. On touch devices it opens the system share sheet; elsewhere it copies to the clipboard.
 - **Sound**: short tones made with the Web Audio API for keypress, mistake, and completion. Can be turned off.
 - **Keyboard**: Tab restarts while you are typing. Escape closes a dialog. Opening Settings during a run abandons the run.
 - **Focus**: if the typing input loses focus, a hint appears over the text. Pressing a letter key moves focus back to the input.
@@ -46,6 +47,7 @@ Everything is stored in `localStorage` under these keys:
 | `typingGameSettings` | mode, duration, word count, category, and the feature toggles                |
 | `typingGameHistory`  | last 50 runs as `{wpm, accuracy, date, mode, key}`                           |
 | `typingGameBests`    | best WPM and its keystroke timings for each settings key, used by Ghost Mode |
+| `typingGameKeyStats` | attempts and misses for each expected character across recorded runs         |
 
 A settings key combines mode, length, and category, for example `time:60s:common` or `words:25w:code`. Common Words with punctuation or numbers adds them to the category, as in `time:30s:common+punctuation+numbers`. Best scores, Ghost Mode, and the chart only compare runs with the same key. Runs that finish in under a second are shown but not saved.
 
 
@@ -87,10 +87,12 @@ <h1>TYPE<span class="accent">SPEED</span></h1>
                         <label for="category-select" class="visually-hidden">Text category</label>
                         <select id="category-select" class="category-select">
                             <option value="common">Common Words</option>
+                            <option value="weak">Weak Keys</option>
                             <option value="general">Quotes</option>
                             <option value="technology">Technology</option>
                             <option value="code">Code Snippets</option>
                         </select>
+                        <p id="practice-note" class="practice-note hidden"></p>
                     </div>
 
                     <div class="control-group right">
@@ -220,6 +222,8 @@ <h2 id="result-title">Result</h2>
                     </div>
                 </dl>
 
+                <p id="modal-keys" class="modal-keys"></p>
+
                 <p id="modal-source" class="modal-source hidden"></p>
 
                 <div class="chart-row">
@@ -252,6 +256,9 @@ <h3>Progress</h3>
 
                 <div class="modal-actions">
                     <button id="share-btn" class="action-btn secondary">Share Result</button>
+                    <button id="practice-btn" class="action-btn secondary hidden">
+                        Practice weak keys
+                    </button>
                     <button id="play-again-btn" class="action-btn primary">Play Again</button>
                 </div>
             </div>
 
@@ -30,6 +30,9 @@ const modalBestElement = document.getElementById('modal-best');
 const modalRawElement = document.getElementById('modal-raw');
 const modalCharsElement = document.getElementById('modal-chars');
 const modalTimeElement = document.getElementById('modal-time');
+const modalKeysElement = document.getElementById('modal-keys');
+const practiceBtn = document.getElementById('practice-btn');
+const practiceNote = document.getElementById('practice-note');
 const shareBtn = document.getElementById('share-btn');
 const playAgainBtn = document.getElementById('play-again-btn');
 const settingsBtn = document.getElementById('settings-btn');
@@ -62,6 +65,7 @@ const STORAGE_KEYS = {
     history: 'typingGameHistory',
     bests: 'typingGameBests',
     settings: 'typingGameSettings',
+    keyStats: 'typingGameKeyStats',
 };
 
 function loadJSON(key, fallback) {
@@ -89,7 +93,7 @@ const DEFAULT_SETTINGS = {
     mode: 'time', // 'time' or 'words'
     duration: 60, // seconds, time mode
     wordCount: 10, // words mode
-    category: 'common', // 'common' or a key of QUOTES (texts.js)
+    category: 'common', // 'common', 'weak', or a key of QUOTES (texts.js)
     isGhostEnabled: false,
     isHardMode: false,
     isSoundEnabled: true,
@@ -98,7 +102,7 @@ const DEFAULT_SETTINGS = {
     isStopOnError: false, // wrong keys do not advance the caret
 };
 
-const CATEGORIES = ['common', ...Object.keys(QUOTES)];
+const CATEGORIES = ['common', 'weak', ...Object.keys(QUOTES)];
 
 function sanitizeSettings(saved) {
     const settings = { ...DEFAULT_SETTINGS };
@@ -140,6 +144,7 @@ const runtime = {
     keystrokes: 0, // characters inserted, including ones later deleted
     mistakes: 0, // inserted characters that did not match
     ghostStrokes: [], // {t: ms since start, i: character index} for Ghost Mode
+    keyStats: {}, // {[expected character]: {attempts, misses}} for this run
     ghostTimeouts: [],
 };
 
@@ -153,6 +158,24 @@ if (!Array.isArray(runHistory)) runHistory = [];
 let bests = loadJSON(STORAGE_KEYS.bests, {});
 if (!bests || typeof bests !== 'object' || Array.isArray(bests)) bests = {};
 
+// Attempts and misses per expected character across all recorded runs.
+let keyStats = loadJSON(STORAGE_KEYS.keyStats, {});
+if (!keyStats || typeof keyStats !== 'object' || Array.isArray(keyStats)) keyStats = {};
+
+// Letters missed most often, by miss rate, among letters tried at least
+// WEAK_MIN_ATTEMPTS times. Used by the Weak Keys category.
+const WEAK_MIN_ATTEMPTS = 5;
+const WEAK_KEY_COUNT = 3;
+
+function weakestKeys() {
+    return Object.entries(keyStats)
+        .filter(([key, stat]) => /^[a-z]$/i.test(key) && stat && stat.misses > 0)
+        .filter(([, stat]) => stat.attempts >= WEAK_MIN_ATTEMPTS)
+        .sort(([, a], [, b]) => b.misses / b.attempts - a.misses / a.attempts)
+        .slice(0, WEAK_KEY_COUNT)
+        .map(([key]) => key.toLowerCase());
+}
+
 // Runs only compete with runs of the same mode, length, and category.
 function settingsKey() {
     const length = gameState.mode === 'time' ? `${gameState.duration}s` : `${gameState.wordCount}w`;
@@ -258,14 +281,14 @@ function pickQuote(categoryQuotes) {
 
 // Random common words with no word twice in a row, plus optional
 // punctuation (capitalized sentences, commas, full stops) and numbers.
-function commonWords(count) {
+function commonWords(count, list = COMMON_WORDS) {
     const words = [];
     let previous = '';
     let sentenceStart = true;
     for (let n = 0; n < count; n++) {
         let word;
         do {
-            word = COMMON_WORDS[Math.floor(Math.random() * COMMON_WORDS.length)];
+            word = list[Math.floor(Math.random() * list.length)];
         } while (word === previous);
         previous = word;
 
@@ -288,8 +311,19 @@ function commonWords(count) {
     return words.join(' ');
 }
 
+// Common words that contain at least one of the given letters. Falls back
+// to the whole list when too few words match.
+function wordsWithKeys(keys) {
+    const matching = COMMON_WORDS.filter((word) => keys.some((key) => word.includes(key)));
+    return matching.length >= 10 ? matching : COMMON_WORDS;
+}
+
 // Returns { text, source } for the next passage.
 function getPassage() {
+    if (gameState.category === 'weak') {
+        const count = gameState.mode === 'words' ? gameState.wordCount : COMMON_CHUNK;
+        return { text: commonWords(count, wordsWithKeys(weakestKeys())), source: '' };
+    }
     if (gameState.category === 'common') {
         const count = gameState.mode === 'words' ? gameState.wordCount : COMMON_CHUNK;
         return { text: commonWords(count), source: '' };
@@ -372,7 +406,12 @@ function handleInput() {
             const pos = unchanged + k;
             if (pos >= quote.length) continue;
             runtime.keystrokes++;
-            if (inserted[k] !== quote[pos]) {
+            const expected = quote[pos];
+            const stat = runtime.keyStats[expected] || { attempts: 0, misses: 0 };
+            runtime.keyStats[expected] = stat;
+            stat.attempts++;
+            if (inserted[k] !== expected) {
+                stat.misses++;
                 wrong++;
                 if (firstWrong === -1) firstWrong = pos;
             }
@@ -525,6 +564,15 @@ function endGame(endTime = Date.now()) {
         runHistory.length = Math.min(runHistory.length, HISTORY_LIMIT);
         saveJSON(STORAGE_KEYS.history, runHistory);
 
+        for (const [key, stat] of Object.entries(runtime.keyStats)) {
+            const total = keyStats[key] || { attempts: 0, misses: 0 };
+            keyStats[key] = {
+                attempts: total.attempts + stat.attempts,
+                misses: total.misses + stat.misses,
+            };
+        }
+        saveJSON(STORAGE_KEYS.keyStats, keyStats);
+
         if (wpm > (previousBest ? previousBest.wpm : 0)) {
             bests[key] = { wpm, keystrokes: runtime.ghostStrokes };
             saveJSON(STORAGE_KEYS.bests, bests);
@@ -620,6 +668,7 @@ function resetGame() {
         keystrokes: 0,
         mistakes: 0,
         ghostStrokes: [],
+        keyStats: {},
     });
 
     runtime.timer = gameState.mode === 'time' ? gameState.duration : 0;
@@ -647,6 +696,12 @@ function updateQuickBar() {
     quickDuration.classList.toggle('hidden', gameState.mode !== 'time');
     quickWordCount.classList.toggle('hidden', gameState.mode !== 'words');
     ghostBadge.classList.toggle('hidden', !gameState.isGhostEnabled);
+
+    const weak = weakestKeys();
+    practiceNote.classList.toggle('hidden', gameState.category !== 'weak');
+    practiceNote.textContent = weak.length
+        ? `Practicing: ${weak.join(', ')}`
+        : 'Not enough mistakes recorded yet. Using all common words.';
 }
 
 function updateHighScoreDisplay() {
@@ -684,6 +739,18 @@ function showResultModal(wpm, accuracy, { isNewBest, previousBest }) {
         modalBestElement.textContent = `Best for these settings: ${previousBest.wpm} WPM.`;
     }
     modalBestElement.classList.toggle('new-best', isNewBest && Boolean(previousBest));
+
+    const missed = Object.entries(runtime.keyStats)
+        .filter(([, stat]) => stat.misses > 0)
+        .sort(([, a], [, b]) => b.misses - a.misses || a.attempts - b.attempts)
+        .slice(0, 3)
+        .map(
+            ([key, stat]) => `${key === ' ' ? 'space' : key} (${stat.misses} of ${stat.attempts})`
+        );
+    modalKeysElement.textContent = missed.length
+        ? `Most missed keys: ${missed.join(', ')}`
+        : 'No missed keys.';
+    practiceBtn.classList.toggle('hidden', weakestKeys().length === 0);
     modalSourceElement.textContent = runtime.quoteSource;
     modalSourceElement.classList.toggle('hidden', !runtime.quoteSource);
     resultModal.classList.add('show');
@@ -971,6 +1038,12 @@ function init() {
 
     shareBtn.addEventListener('click', shareResult);
     playAgainBtn.addEventListener('click', resetGame);
+    practiceBtn.addEventListener('click', () => {
+        gameState.category = 'weak';
+        categorySelect.value = 'weak';
+        saveSettings();
+        resetGame();
+    });
 
     document.addEventListener('keydown', handleKeydown);
 
 
@@ -650,6 +650,7 @@ footer {
 
 .modal-actions {
     display: flex;
+    flex-wrap: wrap;
     gap: 1rem;
     justify-content: center;
 }
@@ -797,6 +798,17 @@ footer {
     color: var(--text-main);
 }
 
+.modal-keys {
+    margin: -0.75rem 0 1.25rem;
+    font-size: 0.85rem;
+    color: var(--text-muted);
+}
+
+.practice-note {
+    font-size: 0.8rem;
+    color: var(--text-muted);
+}
+
 .modal-source {
     margin: -1rem 0 1.5rem;
     font-size: 0.85rem;
 
@@ -946,3 +946,77 @@ test('the result dialog is positioned against the viewport, not the page card',
     const title = await page.locator('#result-title').boundingBox();
     expect(title.y).toBeGreaterThanOrEqual(0);
 });
+
+test.describe('weak keys', () => {
+    test('counts misses per expected key and shows the most missed after a run', async ({
+        page,
+    }) => {
+        await page.addInitScript(() => {
+            localStorage.setItem('typingGameSettings', JSON.stringify({ mode: 'words' }));
+        });
+        await page.goto('/');
+        const quote = await currentQuote(page);
+        const wrong = (c) => (c === 'x' ? 'y' : 'x');
+
+        // Miss the first character twice, fixing it each time.
+        await input(page).press(wrong(quote[0]));
+        await input(page).press('Backspace');
+        await input(page).press(wrong(quote[0]));
+        await input(page).press('Backspace');
+        await input(page).pressSequentially(quote, { delay: 40 });
+
+        const stat = await page.evaluate((key) => runtime.keyStats[key], quote[0]);
+        expect(stat.misses).toBe(2);
+        expect(stat.attempts).toBeGreaterThanOrEqual(3);
+        await expect(page.locator('#modal-keys')).toHaveText(
+            new RegExp(`^Most missed keys: ${quote[0]} \\(2 of \\d+\\)$`)
+        );
+
+        // The totals are saved and survive a reload.
+        await page.reload();
+        const saved = await page.evaluate(
+            (key) => JSON.parse(localStorage.getItem('typingGameKeyStats'))[key],
+            quote[0]
+        );
+        expect(saved).toEqual(stat);
+    });
+
+    test('Practice weak keys starts a run of words containing the weakest letters', async ({
+        page,
+    }) => {
+        await page.addInitScript(() => {
+            localStorage.setItem('typingGameSettings', JSON.stringify({ mode: 'words' }));
+            localStorage.setItem(
+                'typingGameKeyStats',
+                JSON.stringify({
+                    k: { attempts: 10, misses: 5 },
+                    v: { attempts: 10, misses: 4 },
+                    e: { attempts: 100, misses: 1 },
+                    w: { attempts: 2, misses: 2 }, // too few attempts to count
+                    ';': { attempts: 10, misses: 9 }, // not a letter
+                })
+            );
+        });
+        await page.goto('/');
+        await input(page).pressSequentially(await currentQuote(page), { delay: 40 });
+        await expect(page.locator('#practice-btn')).toBeVisible();
+        await page.locator('#practice-btn').click();
+
+        await expect(page.locator('#category-select')).toHaveValue('weak');
+        await expect(page.locator('#practice-note')).toHaveText('Practicing: k, v, e');
+        const words = (await currentQuote(page)).split(' ');
+        expect(words).toHaveLength(10);
+        for (const word of words) expect(word).toMatch(/[kve]/);
+        expect(await page.evaluate(() => settingsKey())).toBe('words:10w:weak');
+    });
+
+    test('hides the practice button until a letter has enough misses', async ({ page }) => {
+        await page.addInitScript(() => {
+            localStorage.setItem('typingGameSettings', JSON.stringify({ mode: 'words' }));
+        });
+        await page.goto('/');
+        await input(page).pressSequentially(await currentQuote(page), { delay: 40 });
+        await expect(page.locator('#modal-keys')).toHaveText('No missed keys.');
+        await expect(page.locator('#practice-btn')).toBeHidden();
+    });
+});