Click an empty position to place your man.
A move consists of walking straight (orthogonally) until you encounter a block.

The blocks come in four different colours and two different sizes. After each of your step, a differently coloured set of blocks shrinks, the sequence being yellow, red, purple, blue, yellow,.... The next colour to be shrunk is shown at the top center border.

Large blocks stop you.
What happens when you encounter a small block depends on the variant:
Variants 1-26: You may stop in front of it or move onto its position. In both cases the small block will be eliminated.
Variants 27-52: You may stop in front of it or move onto its position. Only in the latter case the small block will be eliminated.
Variants 53-78: You have to step onto the block. The small block will be eliminated.
Variants 79-104: You have to stop in front of it. The small block will be eliminated.

You win when you eliminate all blocks.
If you don't manage to eliminate all blocks, try make as many unblocking moves as possible (or leave as few blocks on the board as possible).
If a variant seems too easy, select one with fewer blocks given or one with a larger board. Also, variants 27-104 are more difficult than variants 1-26.

When SmartMoves is activated, you simply click the target position to move your man. Activate it via View/Options/Board/SmartMoves.

Apart from different block-elimination rules, the variants have different board sizes and/or a different number of given blocks.

The name Hiroi was chosen for this game because some variants of it are similar to the Zillions game 'Hiroimono'.
Other related games: Unblock, Adec, Adec-dia, Straight, Straight-dia.