This rule set is a manual translation of the current (2018) Japan Classic Micromouse rules. Some minor changes have been made for the sake of grammar and to accommodate local variance – for example the maze surface.

Micromouse robots

  • Micromice must be free-standing and self-contained. Energy sources using combustion are not permitted.
  • Micromice must not have components – including batteries – added, removed, replaced or changed by the operator during the competition. However, minor repairs and adjustments are acceptable with the approval of the judges. It should be noted that for competitions deemed particularly necessary, replacement of batteries with exactly the same specifications may be permitted.
  • Micromice must not leave any part of in the maze.
  • Micromice must not jump over or climb the maze walls, or use any sensing method likely to cause damage to the maze.
  • The size of the micromouse must, at all times, be able to fit into a 25 cm square when placed on the floor surface. However, there are no height restrictions.

Rules on the maze

  • The sides of the maze walls is white, the top of the wall is red, and the floor is black. The running surface of the maze shall be painted with black matt paint or varnish.
  • The maze is composed of 18 cm x 18 cm unit sections, and the overall size is 16 x 16 sections. The height of the walls is 5 cm and the thickness is 1.2 cm. Passageways between the walls shall be 16.8cm wide.
  • The starting square of the maze is in one of the four corners and departs clockwise. The starting square shall have walls on three sides. The starting square orientation shall be such that when the open wall is to the ‘north’, outside micromouse maze walls are on the ‘west’, and ‘south’. The end point is the centre 4 squares.
  • Square posts, each 1.2cm x 1.2cm x 5cm high, shall be placed at the four corners of each unit square (the lattice points). The micromouse maze shall be constituted such that there is at least one wall touching each lattice point, except the centre of the end point. In addition, all the peripheral walls of the entire maze are present.

Rules on competition

  • The shortest time taken for the micromouse to travel from the start point to the end point is taken as the maze run time of the micromouse.
  • The operator shall not enter information about the maze into the micromouse after the maze has been revealed. In addition, the operator shall not manually correct or partially erase information about the maze during the competition.
  • The maze run always begins from the starting square, and ends when returning to the starting square, stopping for 2 seconds or more, or manual recovery of the micromouse is authorised.
  • If the micromouse returns to the starting square and restarts automatically, it must stop for at least 2 seconds in the starting square.
  • The operator shall not touch the running micromouse unless instructed or authorised to do so by the judges. The competition judge will permit a manual recovery if the micromouse has clearly malfunctioned or is unable to continue running. In addition, a request for recovery under any other circumstances may be accepted on the condition that all memories concerning the maze be erased.
  • Micromice have a duration of 10 minutes, during which they can run up to 5 times. However, for competitions where it is deemed by the judges to be necessary, the time may be reduced to 5 minutes.
  • It is recognised that the micromouse has passed through the timing gate when all parts of the micromouse within 5 cm of the floor surface have entered the end goal area. However, the measurement of the run time is made when the sensor at the start point senses the micromouse and then the sensor at the end point senses the same mouse.
  • The lighting, temperature and humidity for the contest shall be the normal indoor environment. No request for lighting adjustment will be accepted.
  • The judges may ask the operator for an explanation of the micromouse if deemed necessary. At the discretion of the judges, contestants may be asked to stop running, disqualified or other necessary measures taken.
  • The content and award criteria of the competition will be determined for each competition.


  • It is not permitted to load programs and change ROMs during contest. In addition, it is not permitted during the contest to connect the micromouse to a development device or console box independent of the main unit in order to give instructions on program execution.
  • Although it is permitted to remove dust and dirt attached to the tyres with adhesive tape during the competition, solvents etc. should not be used.
  • The micromouse can continue searching the maze further after reaching the end point in each run. In this case, the time from the start point to the end point is recorded.
  • If the micromouse restarts within 2 seconds after returning to the starting point, it is considered that the next run has started, but the timekeeping record of that run is invalid.
  • For adjustment, etc., handlers must not place the micromouse in any area other than the the start square of the maze.
  • Mazes are manufactured with common sense precision, so some dimensional errors may occur. In addition, gaps or steps of up to 1 mm may occur on the wall and floor. In addition, there may be colour variations, discolouration, stains and the like present on the floor or the walls.
  • The timing sensors are transmission type photoelectric sensor The optical axis is horizontal and 1 cm above the floor. Timing sensors are placed at the boundary of the start square and the boundary of any entrances to the goal area.
  • There are no walls or columns in the goal area.