New • Custom rules: build your own line and outside-clue rules in the Workshop and combine them with built-in rule templates • Random puzzles: pick a board size and difficulty to get 1–3 random variant rules, then lock the ones you like and reroll the rest • Variant sudoku hints: step-by-step hints for cage arithmetic, variant chains and more, with a next step when you are stuck • Layered hints: see the technique first, then where to look and the key candidates, or jump straight to the answer Improved • New solving engine: faster hints, ratings and puzzle generation, with explanations for more techniques Other • Bug fixes

New • Pencil handwriting: write digits straight into cells with Apple Pencil; small corner digits become candidates; learns your handwriting • Custom rule sudoku: combine rules into a new puzzle, 4×4 to 9×9 • Input area settings: 5 keypad layouts, customizable key placement, Minimal and Full presets • Lock input: lock a digit, Erase or Candidates for continuous entry • Gesture settings: customizable long-press, double-tap, swipe and Apple Pencil actions • Drag to fill: drag a digit key onto a cell to place it • Display settings: candidate highlight modes, board and font size controls, coordinate labels; reorganized color schemes • Help: help center, guided tour and in-context tips • Redesigned home screen with a new Workshop entry Other • Bug fixes

bug fix

[Big] Variant Sudoku: from 3 to 20 variants • New: Windoku, Center Dot, Anti-Knight, Anti-King, Even-Odd, Consecutive, XV, Kropki, Thermo, German Whispers, Renban, Palindrome, Between Lines, Sandwich, X-Sums, Skyscrapers and Little Killer • Four difficulty levels for every variant, with a fully retuned difficulty curve — Medium bites, Hard means it • Killer Sudoku board redrawn: cage sums moved onto the cage corner so candidates are never covered [New] Variants now play like the classic game • Notes, auto-candidates, pause, error checking, stats and results — all there • 10-color annotations, chain drawing, elimination marks and board snapshots now work in variants too • Stuck? Reveal the selected cell's answer [New] Tap a number, light up the board • With no cell selected, tap a keypad number to highlight every placement and every candidate of that number at once [New] Turn a photo into a theme • Generate a custom theme from any photo, with 30 fine-tune options • New in-game palette: brightness, font size and highlight styles, one tap away [Improved] • New "chip" style for candidate highlighting • Weekly leaderboard scoring fix • Many interface refinements and stability fixes

[Big] Tutorials, completely rebuilt: a full learning path from basics to the extreme • Theory courses arrive: Foundations / Chains / Rank Theory / Deadly Patterns / Exocet — 5 courses, 27 chapters, with real-board illustrations and concept cards • Exocet theorems chapter: Mirror Sync, Target Pair, Locked Member, Same-Box and Region-X theorems each come with a dedicated diagram highlighting base, targets, mirror cells and Region X • Technique explainers: six bilingual sections for all 70 techniques (what it is / why it works / the math / how to scan / reading highlights / checklist) • Step-by-step walkthroughs: explanations now follow the actual structure of the step in front of you, not a generic template • Learning path aligned with the seven game difficulties: stage challenges, mastery profiles and review suggestions • Practice upgraded: classic curated puzzles plus unlimited isomorphic variants; rare techniques like the Trivalue Oddagon are now practicable [New] Score Leaderboards • Engine-rated scores accumulate into all-time and weekly boards • No sign-up needed — play under an auto nickname, rename anytime [New] Welcome Onboarding • A fresh three-page intro: pick your level, score a quick win, find your way around [Better] Hints • Five-level progressive reveal: technique → area → candidates → eliminations → full explanation. Think first, no spoilers • Hint cards link straight to lessons and explainers [Better] • Replay player: technique-visual toggle, key-steps-only mode, staged loading • Draft tools now offer 10 colors across chains, shapes and regions • Advanced engine reliability: automatic recovery from background termination

[New] Analyzer Studio (all-new standalone workbench) • Full-screen analyzer : load any puzzle for auto rating (ER + score) and a complete solve path • Solve-path player: step through every technique with explanations; draggable score-colored progress bar • Skip basic moves: singles, locked candidates and subsets no longer count as steps — jump straight to the key techniques • Alternative techniques: enumerate every possible move at any step and replace it to recompute the path • Revamped puzzle picker: Recent / Favorites / Imported / Library tabs with thumbnails and difficulty filters [New] Analysis Sharing • Composable image: toggle & drag-reorder blocks — no-hint board / hinted board / result board / engine notes / difficulty report — plus a custom caption • One-tap Solve GIF / long image: original board + difficulty report + every step with hints • Difficulty report: full score-colored band + technique counts [New] Puzzle Sharing Upgrade • New share cards with QR codes; share as image, link, or code • Short links & universal links: friends tap a link and the puzzle opens right in the app • Board images in three flavors: initial / current / with hints (WYSIWYG)

[New] Draft System 2.0 • Seven marking tools: cell coloring, candidate coloring, logic chains, pre-delete/delete marks, mini regions, free drawing • Four chain types (strong/weak/construction strong/weak) with smart straight-or-curved rendering, matching hint visuals • Six-color palette (red/blue/green/yellow/purple/gray) + custom color picker • Full undo/redo, long-press erase, apply pre-deletes to notes in one tap • Share a snapshot of your annotated board [New] Daily Challenge Calendar • All-new gold-themed calendar, adaptive light & dark • Complete any difficulty to light up the day; finish them all for a gold trophy • Monthly medals: bronze/silver/gold unlocked by days completed • Make up missed days within the current month (streaks & leaderboard unaffected) [New] Tutorials × Advanced Engine • Practice puzzles, interactive lessons and endgame training now generated and hinted by the advanced engine • New "Full Solve Replay": step-by-step playback of an entire solution path • Onboarding adds a "First Technique" interactive challenge and a learning path card [New] Appearance & Settings • Two new themes: Classic White II & Classic White III • Three-level candidate note depth (light/standard/deep) • Settings restructured: language on top, dedicated theme page [Improved] • Refreshed multiplayer battle UI end to end • Solve analysis fully engine-rendered, consistent with hint highlighting • Analyzer step panel: mini dock, prev/next with auto-scroll, single-row filters • Faster technique training generation: multi-tier cache + background prefetch, difficulty-aware puzzles • Fixed technique-config crosstalk causing generation failures and inconsistent ratings

This update brings a smarter solving experience across the board: • All-new advanced solving engine: sharper hints, instant puzzle generation, and a true difficulty rating for every puzzle • Redesigned puzzle library: continue playing, smart recommendations, browse by difficulty, plus search and favorites • Puzzle Workshop: generate puzzles by difficulty, rating range, or even a specific technique • Much better photo recognition: improved accuracy, pencil-mark detection, and paste-to-import from images • Daily Challenge difficulty is now true to its label, and you can jump straight to the next puzzle after winning

[Improved] Unified Full-Screen Library UI • Library puzzles now open in full-screen modal, matching the home-screen new-game experience • Title, SE/H rating, Settings / Restart / Replay / Share all available • Back button auto-switches between "Library" and "Home" based on entry point [New] Global Recents Tracking • Library's "Recents" tab is now global: every classic home-screen new game is auto-tracked • Variant Sudoku (Killer / Diagonal / Jigsaw) excluded to keep the list clean • Up to 100 most recent puzzles, sorted by latest

[Improved] Hint Visualization Overhaul • Step-by-step chain demonstration: Forcing Chains, AIC and other complex techniques now show deduction process node by node • Each step displays candidate changes after assumptions, clearly showing how deductions lead to contradictions or conclusions • ALS technique highlighting improved: clearer group boxes, more precise link endpoints • Fish technique visuals refined: removed cluttering lines, kept clear row/column grid markers [New] Technique Preference Management • 9 trial-and-error techniques disabled by default (Forcing Chain family, Dynamic Chains, etc.) • Backtracking kept as fallback to ensure hints are always available • Enable/disable any technique anytime in Settings • 4 sorting modes to browse and manage 77 techniques [Improved] Full Bilingual Support • All technique names, hint explanations, and UI text fully support Chinese/English switching • Fixed display issues in English mode [Fixed] • Fixed technique sorting and highlighting issues • Fixed Discontinuous Nice Loop link rendering errors • Improved overall hint system performance and stability

[Improved] Solution Path Visualization Redesign • Completely redesigned solution path browser: fixed board + top/bottom navigation + scrollable step cards • Full theme color support: path highlights, candidate marks, and strikethrough all follow your theme • Removed AIC elimination arrows for a cleaner look [Improved] Hint Highlighting Overhaul • Naked/Hidden Single: related cells now include all cells in the same row/column/box for full reasoning context • Hidden Pair/Triple/Quad: added same-unit empty cells as reasoning context • Simple/Advanced Coloring: removed complex chain lines, kept dual-color backgrounds for clarity • Swordfish/Jellyfish: related cells now show the complete row×column grid to visualize the fish pattern • ALS techniques: use background colors to distinguish ALS groups, removed cluttered lines [New] Learn-by-Playing Tutorial • New guided tutorial mode: learn Sudoku while solving real puzzles • Step-by-step guidance with interactive actions for quick onboarding [New] App Rating Prompts • Auto-prompts after 3rd, 10th, and 30th puzzle completion [Improved] Brand Refresh • Unified branding to "SudokuFang" (数独芳) • Updated share cards and web sharing page visuals [Fixed] • Fixed crashes in certain practice mode scenarios • Fixed multiplayer connection issues with network check alerts

[New] Photo Alignment — Custom Camera + Grid Guide • New "Align & Capture" mode: built-in 9×9 grid overlay for precise alignment • Semi-transparent mask highlights the alignment area with bold box separators • No more skewed photos — significantly improved OCR recognition accuracy [Improved] Image Recognition Enhancement • Smart candidate filtering: automatically distinguishes pencil marks from main digits • 6/9 confusion auto-fix: rule-based correction for conflicting 6s and 9s • New "6↔9" flip button: one-tap to swap all 6s and 9s manually [New] Comprehensive User Guide • 12 chapters, 52 feature entries covering all game functions • New chapters: Learning System, Share & Export, Rankings, Platform Integration • Added missing docs for X-Ray, input mode switching, long-press popover, and more [Fixed] • Fixed a critical crash when tapping the Hint button • Added "Contact Author" entry in Settings → About

【新功能】每日挑战 2.0 + 全球排行榜 • 每日挑战系统全面升级，新增多难度选择 • 全球排行榜：查看全球玩家名次，按用时排名 • 挑战好友：分享谜题链接，比较你们的成绩 【新功能】4 种新解题技巧（共 53 种） • WXYZ-Wing：四数翼方法，扩展 XYZ-Wing 的高级候选消除 • X-Cycle：交替推理链循环，发现矛盾进行消除 • Franken-Fish：跨宫鱼型技巧，突破标准 Fish 的行列限制 • 避免矩形（Avoidable Rectangle）：利用唯一解特性消除候选 【新功能】解题回放 GIF 导出 • 完成数独后可将解题过程导出为动态 GIF • 一键分享到社交平台，展示你的解题技巧 【新功能】在线谜题分享 • 生成专属谜题链接，好友点击即可在网页上解题 • 分享者成绩对比：好友完成后可看到你的用时和排名

【新功能】解题路径分析器 • 解题路径回放：浏览最优解法的每一步操作，学习高效解题思路 • 技巧统计对比：统计解法中各种技巧的使用频率，对比自己的解题风格 • 链线可视化：推理链路以连线形式直观展示在棋盘上 【新功能】X-Ray 候选数可视化 • 全新 X-Ray 模式：以可视化方式展示候选数分布，快速定位关键格 • 提示技巧自定义：自由配置提示系统使用的技巧范围 • 动画教学增强：新增动画演示，提升技巧学习体验 【新功能】连续操作模式 • 连续候选模式：连续标注多个候选数，无需反复切换 • 连续擦除模式：批量擦除候选数，提升操作效率 • 技巧偏好评分：根据你的解题偏好适配难度评分 【多语言完善】

【重大更新】教学模块全面升级 • 49 种技巧全覆盖：每种技巧都有互动 Demo + 分步推理讲解 • 新增 50+ 道互动练习题：29 种高级技巧新增独立练习，告别重复练同一题 • 新增 4 种技巧教学：唯一矩形 Type3/Type4、超级宫、链推理 • 练习计时：记录每次练习用时，精准追踪学习效率 • 练习结果完整记录：成功和失败都纳入掌握度评估 【引擎修复】 • 修复 UR Type2 端点排序导致的误判 • 修复 3D Medusa / ALS 推理链定位异常 • 修复 W-Wing 端点排序不一致 • 修复高难度跳过技巧时的回溯逻辑 【稳定性优化】 • 修复锯齿数独引擎潜在闪退 • 修复 OCR 图像导入潜在闪退 • 修复成就合并时进度丢失 • 修复存档保存抖动问题 • 修复多处 UI 渐变色闪退风险

【新功能】提示模式切换 • 单步提示：每次只给一步操作（消除候选数或填入），细粒度辅助 • 单格提示：完整推导链逐步展示，学习解题思路 • 可选「基于盘面候选数」：使用你标注的候选数进行分析 • 默认单步模式，在设置中随时切换 【新功能】多人对战增强 • iPad 全屏对战：对战界面改为全屏展示，棋盘大小与单人模式一致 • 全部候选数填充：多人对战支持全部候选和单格候选，与单人模式一致 【优化】数独技巧命名规范化 • 12项技巧名称对齐社区标准：涡轮鱼→多宝鱼、几乎锁定集→待定数组等 • 所有教程、提示、题库中的技巧名同步更新 【修复】 • 修复 iPad 对战棋盘大小不一致问题 • 修复技巧描述中的术语不规范

【新功能】历史记录增强 • 恢复对局：从历史记录直接进入之前的对局，继续下棋或复盘 • 自定义命名：左滑记录重命名，为重要对局标注备注 • 导入题库：左滑记录一键导入到个人题库，方便重玩和分享 • 可恢复标记：有棋盘数据的记录显示恢复图标(↺) 【新功能】完整软件使用指南 • 7大功能分组：游戏模式/基本操作/辅助工具/历史记录/题库系统/统计与成就/个性化设置 • 30+ 条详细说明，覆盖每一项功能 • 入口：解题教学 → 使用指南 【修复】 • 修复 SwiftData schema 兼容性问题，避免数据丢失 • 数据获取优化，提高可靠性

【新功能】草稿标注系统 • 候选数上色：5 种颜色标记关键候选数 • 格子上色：用颜色高亮重要区域 • 逻辑连线：绘制强链/弱链，支持不同颜色 • 放大弹窗：精准选择小格子中的候选数 【优化】提示系统增强 • 提示技巧连接线：直观展示推理链路 • 最后一步数字高亮：引导填入答案 • 切换面板自动关闭提示，避免高亮残留 【优化】操作体验 • 新增撤销系统优化（支持批量candidates撤销） • 点击空白区域取消选中 • 擦除按钮智能清理候选数 • iPad 横屏三面板布局（填格子/提示/草稿） • iPhone 竖屏固定高度面板，布局更稳定 【修复】 • 修复提示高亮动画卡死问题 • 修复教学练习棋盘数据错误