The “coming from” part is basically for the amphibious assault part of that rule. I will try to clarify this with an example:
Let’s use Sea Zone 6 which borders Japan and Korea and has the Kamikaze symbol.
1 – Japan has warships in SZ 6. USA sends warships to attack the Japanese fleet. In this case, the Allied player is attacking Japanese units in a sea zone with a kamikaze symbol, so Japan may use kamikaze if he/she wishes.
2 – Japan has NO warships in SZ 6. USA sends warships to SZ 6 along with transports full of land units to invade Korea. In this case, since there was no naval battle, the US Navy has already occupied SZ 6 and the amphibious assault on Korea is coming from SZ 6. Since SZ 6 has a kamikaze symbol, Japan may use kamikaze. This will count as a sea battle so any battleships and cruisers can NOT use shore bombardment.
SPECIAL NOTE: Kamikaze attacks can only be made on surface warships, NOT on submarines or transports. So, if Japan had no warships in SZ 6, and had no planes to scramble from Japan’s airbase, USA could move the transports in the combat move and invade Korea without suffering Kamikaze. Assuming USA takes Korea, then the USA player could move warships to SZ 6 to protect the transports in the NCM without suffering Kamikaze attacks. Also, even if Japan had planes to scramble, USA could send carrier based planes to fight the Japanese scramble planes and cover the transports because Kamikaze does not work on allied planes either.