SameGame

SameGame (also known as Chain Shot!, Clickomania, or Bubble Breaker) is a tile-matching puzzle played on a grid of colored blocks. The player removes groups of two or more connected blocks of the same color by clicking on them. When blocks are removed, the blocks above fall down due to gravity, and empty columns collapse to the left. The goal is to clear the entire board or, more commonly, to maximize the score by removing larger groups, which are worth exponentially more points.

Rules

1. A rectangular grid (commonly 15x10) is filled with randomly colored blocks, typically using 3-5 colors.
2. The player clicks on a block to select its connected group — all blocks of the same color that are horizontally or vertically adjacent.
3. A group must contain at least 2 blocks to be removed.
4. When a group is removed, blocks above the gap fall down due to gravity.
5. When an entire column becomes empty, the columns to its right shift left to fill the gap.
6. The game ends when no more groups of 2+ connected same-colored blocks exist.

Scoring

• A group of N blocks typically scores (N-2)^2 points (or a similar quadratic formula).
• Larger groups score disproportionately more: removing 5 blocks scores 9 points, but removing 10 blocks scores 64 points.
• A bonus is usually awarded for clearing the entire board (e.g., 1000 points).
• Single isolated blocks remaining at the end are penalties in some versions.

Strategies

• Prioritize Large Groups: Due to quadratic scoring, one group of 10 is worth far more than two groups of 5. Build up large groups before removing them.
• Top-Down Thinking: Removing blocks from the bottom causes cascading shifts that can create or break groups above. Think about how gravity will rearrange the board.
• Column Management: When a column empties and columns shift left, new adjacencies are created. Use this to merge previously separated groups.
• Color Isolation: Try to arrange the board so that one color becomes dominant in a region, enabling a single large removal.
• Delay Small Groups: Resist removing small groups early. They might become part of a larger group as the board shifts from other removals.
• Clear from the Edges: Working from the sides toward the center often creates more opportunities for column collapse and group merging.

SameGame was originally created in 1985 by Kuniaki Moribe under the name "Chain Shot!" for the NEC PC-9801 computer in Japan. The original game used a 10x10 grid with three colors and introduced the core mechanic of removing connected same-colored groups with gravity.

The game gained wider recognition in the early 1990s when Eiji Fukumoto independently created a similar game called "SameGame" for the Unix/X Window System in 1992. This version spread through the open-source community and established the name "SameGame" internationally. The game was also included in the KDE and GNOME desktop environments for Linux, giving it broad exposure among computer enthusiasts.

SameGame has been extensively studied from a computational perspective. In 2004, Biedl, Demaine, Demaine, Fleischer, Jacobsen, and Munro proved that determining whether a SameGame board can be completely cleared is NP-complete, even with only 2 colors. This means there is no efficient algorithm guaranteed to find optimal play. Despite this, the game's relatively small boards make heuristic and AI approaches effective. Various AI competitions have been held to find the best SameGame-playing algorithms.

The game has appeared under many names across platforms: Bubble Breaker on Windows Mobile, Clickomania on the web, JawBreaker on Palm OS, and many others. Its satisfying chain-reaction mechanic and simple rules have made it one of the most enduring casual puzzle games, with modern versions available on every platform. The quadratic scoring system creates a compelling risk-reward tension that rewards patience and planning over hasty clicking.