I present to your attention a number of tasks, where the goal will be to determine whether the item marked with a cross is a foul or not. You can find information about the fouls themselves here. Fouls are used exclusively in the rules of renju (they are absent in the rules of gomoku). The analysis of these problems will help you understand what the concept of a foul is.

The tasks are divided into three parts: the first part is “Walk”, simple tasks that anyone who has even a cursory acquaintance with the basic definitions and types of fouls will master. The second part is “Gatherings”, the tasks are more difficult, which already provide more interesting examples and may take more time and effort. The tasks in the third part – “Long Evening” – are the most complex and interesting, the solution of which will require a certain depth in understanding fouls.

You can send answers for self-test (for those who want to) to Toxaz in a personal. A big request is to send detailed answers: if you think that there is a foul in some problem, then indicate which foul, if you think that there is no foul, then indicate why. If any tasks cause you difficulties, then I will definitely help you deal with them

Part one “Walk”

№1  №2  №3  №4
№5  №6  №7  №8  №9   №10 

Part two “Gatherings”

№1   №2   №3
№4  №5  №6
№7  №8 

№9  №10 

Part Three “Long Evening”

Note: The last five problems have a coordinate system for ease of discussion. The last two tasks, as they say, with an asterisk, i.e. the most difficult. If you manage to figure out at least one of them, then you have mastered the concept of a foul very well and in a real game it will not be difficult for you to figure out whether a foul is in front of you or not (in practice, such terrible positions generally do not occur)

№1   №2   №3
№4  №5  №6
№7  №8
№9*  №10*