空當接龍（FreeCell）是全球最受歡迎的益智紙牌遊戲之一，隨微軟 Windows 系統預裝而廣為人知。與蜘蛛接龍、新接龍不同，空當接龍幾乎每一局都能破解，考驗玩家的邏輯推理能力與遠見規劃。
遊戲規則：
- 牌堆共 8 列，全部 52 張牌正面朝上發出
- 右上角 4 個「基礎牌堆」：每個花色從 A 開始依序堆疊到 K
- 左上角 4 個「空格」：可暫存任意一張牌
- 移牌規則：在牌列中，只能將牌放在比其大一點且顏色相反的牌上（紅黑交替、數字遞減）
- 利用空格數量決定可一次移動的最大牌數（超級移動規則）
特色功能：
- 支援觸控與滑鼠操作，完美適應手機、平板、電腦
- 每局唯一編號，可重複挑戰同一局牌面
- 提示系統：自動找出可行的移法
- 悔棋功能：無限次悔棋，輕鬆應對失誤
- 自動完成：局面明朗時一鍵送牌上基礎堆
- 步數統計與勝率紀錄
玩法技巧：
- 優先將 A 和 2 移入基礎堆
- 空格是寶貴資源，勿輕易佔用
- 空列能讓更多張牌同時移動
- 多想幾步再行動，避免牌局死鎖
FreeCell Solitaire is one of the world's most beloved card games, famous for being pre-installed with every version of Microsoft Windows. Unlike many solitaire variants, almost every FreeCell deal is solvable — success depends entirely on skill, strategy, and foresight.
How to Play:
- All 52 cards are dealt face-up into 8 tableau columns
- Move all cards to the 4 foundation piles (top right), built by suit from Ace to King
- Use the 4 free cells (top left) as temporary holding spots for single cards
- In the tableau, place cards on a card of opposite color and next higher rank
- The number of empty free cells and columns determines how many cards you can move at once (super-move rule)
Features:
- Works on mobile, tablet, and desktop — touch and mouse supported
- Unique game number for every deal — replay any hand you've seen before
- Hint system highlights a valid move when you're stuck
- Unlimited undo — go back as many moves as you need
- Auto-complete — one tap finishes the game when the outcome is clear
- Move counter and win-rate tracking stored locally
Strategy Tips:
- Get Aces and 2s to foundations as early as possible
- Free cells are limited — don't fill them all at once
- Empty columns are powerful; use them to move longer sequences
- Think several moves ahead to avoid a deadlock