先學會叫出威脅的名字
五子棋的攻防全部圍繞四種棋形展開。活三：三子相連且兩端都空，下一手可以變成活四。眠三（死三）：三子有一端被擋，威脅大減。衝四：四子只有一端能成五，對手必須立刻擋，否則直接輸。活四：四子兩端皆空——這是勝定形，對手擋住一端你就從另一端成五。能在盤面上即時認出這四種形，攻防判斷就有了語言。
活三為什麼必擋
放任對手的活三，下一手就是活四，而活四無解。所以看到對方活三，除非你自己有衝四或更快的殺著，否則必須立刻回應。擋的位置有講究：擋在「活」的那一端。如果對手三子的一端本來就被你的棋子或邊線堵住，那已是眠三，不必浪費一手去補。新手最常見的失誤就是被假威脅騙走節奏，去堵一個其實成不了五的方向。
衝四是免費的節奏
衝四對手不得不應，你等於免費獲得一手棋。連續的衝四可以一路牽著對手走，把自己的棋子逐步佈置到理想位置——這叫「借衝四行棋」。但要注意衝四打完之後你得到了什麼：如果衝完對手反而形成反擊，那這口「先手癮」就過得不值。
單威脅贏不了棋
對手每一手都能擋掉你的一個威脅，所以單一活三、單一衝四永遠不夠。真正的勝負手是雙威脅：一子同時形成兩個活三（雙三），或一個衝四加一個活三（四三）。對手只有一手棋，擋住其中一個，另一個就成立。中盤的全部努力，本質上都是在為某一步「一子雙形」做準備——讓你的棋子交叉點越多，這種機會就越常出現。
開局把子下「厚」
本站規則無禁手，黑棋先行優勢明顯，理論上無禁手的五子棋黑棋必勝。開局階段把棋子集中在天元附近，讓每一顆子同時參與橫、豎、斜多個方向的潛在連線；下得太散的棋子各自為戰，永遠湊不出雙威脅。執白時則要有防守意識：前幾手主動貼近黑棋，斷開它的髮展方向，而不是自己另起爐灶。
在本站怎麼玩
棋盤為 15×15 標準尺寸，你執黑先行，落子後不可移動。最後落下的一子會以粉色高亮，複盤對手的應手時很有用。三檔電腦難度中，困難檔會主動製造和攔截雙威脅，適合拿來驗證上面的攻防概念。勝場與對局數記錄在目前瀏覽器。
下一盤試試看：進入五子棋，刻意做一次四三殺。
Name the threats first
All gomoku tactics revolve around four shapes. An open three: three stones in a row with both ends empty, one move away from an open four. A blocked three: one end sealed, far less urgent. A simple four: four stones with only one way to make five — the opponent must answer immediately. An open four: four stones with both ends empty, which is a won position, since blocking one end lets you finish on the other. Once you can name these shapes at a glance, attack and defense become a language instead of a guess.
Why an open three demands an answer
Ignore an open three and the next move is an open four, which cannot be stopped. So unless you hold a four of your own or a faster kill, respond at once — and respond at the live end. If one end of the three is already sealed by your stone or the board edge, it is merely a blocked three and needs no move at all. The classic beginner error is losing tempo to fake threats that could never become five.
Fours buy free tempo
A simple four forces a reply, which effectively hands you a free move. Chains of fours can drag the opponent around the board while you place stones exactly where you want them. Just audit what each four actually buys: if the forced sequence ends with the opponent better placed than before, that tempo was spent, not earned.
Single threats never win
Your opponent gets one move per turn, so one threat per turn is always answerable. Games are won by double threats: one stone creating two open threes at once, or a four plus an open three. One reply cannot cover both. Everything in the middlegame is preparation for that single double-purpose stone — the more intersections your stones share, the more often the chance appears.
Open thick, not wide
This site plays without forbidden moves, so black's first-move advantage is large — with perfect play, black wins the freestyle game. Open near the center and keep early stones connected, so each one participates in several directions at once; scattered stones fight alone and never assemble a double threat. As white, lean into contact early and cut black's directions instead of building a separate camp.
On this site
The board is the standard 15×15; you play black and move first, and stones never move once placed. The last move is highlighted in pink, which helps when reading the computer's reply. Of the three difficulty levels, hard actively builds and blocks double threats — a good sparring partner for everything above. Wins and games are stored in the current browser.
Theory sets fastest over the board: open Gomoku and land a deliberate four-three.