本系统主要有以下4个模块，每个模块对应一个程序包：

1、engine：搜索引擎包，系统的核心部分。

2、message：网络对战过程中各种消息及其传递机制的类实现包。

3、main：主界面实现包。

4、pieces：棋子及其相关类实现包。

现就各个包中的要点给与说明。

-The system has the following four modules, each module corresponds to a package: 1, engine: Search engine package, the core of the system. 2, message: the process of online play, a message and its delivery mechanism class package. 3, main: the main interface package. 4, pieces: pawn and its related class implements package. Now give instructions on the main points of each package.