Chess Variants/Grid Chess

Introduction
Grid Chess is a variant played on a specially marked grid board.

History
Grid chess was created by Walter Stead in 1953. The variant and its main gimmick have been used in fairy chess problems.

Rules
Grid chess is played on the standard 8 by 8 board, marked with a grid of lines that partition the board into sectors. There are several different ways to arrange these lines, but the most common arrangement divides the board into 16 2 by 2 squares.

The rules are the same as standard chess, with one addition: for a move to be legal the piece must cross a grid line. So for example in the diagram the black queen could not move to e1, f1 or f2 as those moves would not take it over a grid line - and so the white king is not in check despite the two pieces' proximity.

Sub-variants
This chess variant does not not have any notable sub-variants.