Othello First Move and Book Openings: Patterns and Plans

When playing against AI on a smartphone, you may often find yourself at a disadvantage within the first few moves of the opening phase, leaving you with nowhere to play in the midgame. The first move in Othello is chosen from 4 squares adjacent to the 4 central discs: d3, c4, e6, and f5. Rotating or reflecting the board makes all of them identical, so there is no real difference between them. The turning point lies in White's response to that first move and how the subsequent book openings branch out.

The most critical guideline in the opening phase is not to capture many discs, but to keep the number of flipped discs low so that you deny your opponent playable choices. Understanding the major book opening patterns branching from the first move makes it easier to seize the initiative from the midgame onward.

First Move Basics and Branching from White's Response

This shows the position right after Black plays f5 on move 1. White has 3 ways to outflank: vertically at d6, diagonally at f6, or horizontally at f4. Excluding moves that become identical by rotating the board, the choice of this move 2 significantly branches the subsequent development.

White playing d6 is called the perpendicular opening, leading to the most standard book openings. Playing f6 is called the diagonal opening, and playing f4 is called the parallel opening. Intermediate players should first learn the lines starting from d6, which appear most frequently. Both Black and White keep their discs dense in the center, advancing their turns while striving not to expose discs to the outside.

Opening Intent in the Three Major Openings: Rabbit, Tiger, and Cow

This shows the Rabbit position where Black has played up to move 5 at e3. By playing e3 here, Black flips an interior disc while maintaining a solid shape without needlessly contacting outside empty squares.

Traditional book openings bear animal names, with Rabbit, Tiger, and Cow being representative. Each has a set sequence where squares are chosen with specific intentions.

• Rabbit: f5 d6 c5 f4 e3 - Known as the standard opening path. Both players keep discs inside, encouraging the opponent to surround the exterior. It offers high flexibility in the midgame and tends to create a calm contest.
• Tiger: f5 d6 c3 d3 c4 - A sharp sequence where Black dives into c3 against White's d6. Discs cluster in the center early and narrow both players' turn options, making it ideal for running the opponent out of moves in the midgame.
• Cow: f5 f6 e6 f4 e3 - A representative sequence when White chooses the diagonal move f6. Focusing on diagonal lines, Black secures a central foothold while looking to expand toward the edges.

The purpose of studying book openings is not simply memorizing move sequences. Every book opening shares the goal of minimizing openness around your discs to limit where your opponent can play. Understanding the intent behind each move helps you naturally find composed moves even when the AI deviates from known lines.

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The fastest way to grasp these ideas is to try them out. You can play to the very end against an AI that thinks on your device, even with no mobile signal.

Transition to the Midgame and Corner Battles

After establishing your opening structure, the game shifts to midgame tactics. The biggest danger in the midgame is playing into hazardous squares around the four corners. The four corners (a1, h1, a8, and h8) are safe havens that can never be flipped once taken. Carelessly playing into an X-square (b2, g2, b7, g7) diagonally adjacent to a corner, or a C-square (such as a2, b1) adjacent along an edge, allows your opponent to seize a corner.

Many players who collapse in the midgame against AI run out of moves and are forced to play into an X-square. To prevent this, it is essential from the opening phase to use quiet moves, flipping only interior discs and avoiding opening new exterior empty squares.

In the smartphone Reversi app Patent War, you can play against an AI that strengthens across 50 stages, providing a great testing ground for opening ideas and midgame disc control. Higher-level AI accurately targets positional weaknesses and mobility, sharpening your strategy after following book openings.

Applying Parity to Secure an Endgame Win

Once you navigate the midgame evenly or better using book openings, you need to master closing out the endgame. Parity is an indispensable technique for controlling the final phase. In the endgame, empty squares separate into several isolated regions across the board.

Parity means playing first into an odd region with an odd number of empty squares so that you get to play the final move in that region. If your opponent has no move left there after your turn, they must start on another even region. Conversely, you should avoid entering an even region first. Letting your opponent play into an even region first lets you take the remaining square, guaranteeing you claim the last move there.

Following book openings from the first move is preparation to set up favorable parity in the endgame. Conserving moves in the opening phase, restricting the opponent's options in the midgame, and accurately analyzing odd and even regions in the endgame will dramatically boost your win rate against AI.

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Patent War, a Reversi app traveling through a steampunk world. You can start your journey and games against the AI for free.