How to read the state of 300 circuits (and connect to Arduino/Pi) for a closed/open state?

Question

Arduino

For a board game, you need to monitor the status in the region of 200-300 contacts (circuits) in real time. The figures on the field, when installed in certain places, close and open the circuits, these "bits" must be able to be understood. Something like in the keyboard, but it is desirable to do without membranes (pressing the figure is not strong). How can this be done in the simplest and most accessible way in terms of production?

Answer 1

Classically - a matrix.
At each intersection there is a reed switch and a diode. A sweep is applied to the horizontal, usually through a decoder, and the state is removed from the verticals.

Answer 2

One of the options is a membrane keyboard on top of a steel plate., Into the figurine a small neodymium magnet with China. and the figurine is more stable and does not fly off into the field, and the moment of sticking is clear for the person who is rearranging, and the contact is strong.