title: Hotaru Beam
text: # Hotaru Beam
  
  Hotaru Beam (lit. 'firefly beam') is a binary-determination logic puzzle published by Nikoli.
  
  ## Description
  
  Hotaru Beam is played on a rectangular grid, usually of dashed lines, in which numbers in circles appear at some of the intersections on the grid. Additionally, each circle has a dot on one of the grid lines leading into the circle.
  
  ## Rules (translated from Nikoli)
  
  * Draw a line from each white circle's black dot to any white circle, following the grid's horizontal and vertical markings.
  * Lines cannot be drawn from a black dot to another black dot, nor can they be drawn from a white circle not at its black dot to a white circle not at its black dot.
  * No crossing or branching of lines is acceptable. At the end, the drawn lines will connect all white circles to form a single, contiguous network.
  * The number on the white circle dictates how many times the line you draw from its black dot must bend before it meets another white circle.
  
  ## Solution methods
  
  A circle with 0 on it (not the same as a blank circle) is a given: It will have at least one line going straight in the direction of the dot until it hits another circle. Each circle will have a line coming out of it in the direction of the dot. Since turning at the corner of the grid counts as a turn, a 1 circle near the corner may be forced to simply continue along the edge of the grid.
  
  