If any two of the LOF enter the target hex through non-adjacent hexsides, then the attack strengths of all attacking units are raised by one before adjusting for range attenuation. If the Line of Sight passes exactly through the length of a blocked hexside then the Line of Sight is considered to be blocked. If the Line of Sight passes exactly through the length of a hexside of a blocking terrain hex then the Line of Sight is considered to be blocked. In all cases the defending unit gets the benefit of the doubt. Off the board artillery and all on-board H class units may fire smoke.
Smoke blocks the Line of Sight like any other blocking terrain hex.
When smoke is fired it effects the impact hex and the six surrounding adjacent hexes. Smoke lasts from the end of the combat phase in which it is fired to the end of the plotting phase of the next turn. This means that if during the plotting phase a unit can not trace a Line of Sight to the target hex because of the smoke then no fire may be plotted to the target hex. Units in a smoked hex may see out of them and fire from them. A unit in a smoked hex may be spotted if either they fire from the smoked hex and are seen or if the spotting unit is within three hexes of the smoked hex.