Copyright (c) ? Marcus Salo

This game is played on an empty 1x9 board. Each player has 4 stones off board.

DROP PHASE - Initially, at each turn, each player drops one stone on an empty cell, until all eight stones are on board.
MOVE PHASE - At each turn, each player must do one of the following actions:
Pass his turn.
Move a stone to an adjacent empty cell.
Move takes precedence over passing.
Jump over one enemy stone and capture it.
Jumps take precedence over movement.
Jumps are multiple.
GOAL - A player wins if just one of the following conditions occur: (i) he captures all enemy stones; (ii) his last stone occupies the same color cell (in these diagrams, b1 for Green and h1 for Red), or (iii) he passes three consecutive times.
An example

Green's turn. He moves d1e1. Then, Red must capture f1:d1 and Green wins by moving his last stone at a1 to b1. 

Some words from the author: I think I have created the simplest strategy game. I call it Motala Strom (isn't that a really catching and commercial name), that is the river that flows through my beloved Norrkoping, Sweden. [...] I have tested this game with Zillions thousands of time and to my surprise, it seems to work and actually be very challenging and have a lot of depth and strategy.