ddp59,
Sometimes I get so wrapped up in the question that I forget the obvious. Your answer immediately reminded me that the Japanese, at first, used regular transports to reinforce Guadalcanal! So, method 1, which I entirely overlooked, was transport ships, a correct answer!
US naval patrols and the Catcus airforce made this method impossible to sustain, so the Japanese used destroyers, (another correct answer) to make fast runs on moonless nights into the off-load area, unload their cargo and then get out quickly. This 2nd method was called operation Nezumi, or, loosely in English, "Rat Transportation." Increasing danger to the destroyers led to a variation of this method. The Japanese filled 200-240 empty fuel drums half full of supplies, stashed them on the weather decks, got close to the beach, shoved them overboard and left immediately, leaving the troops onshore to haul in the floating drums using lines tied to them.
In a final effort to save their destroyers, the Japanese tried a 3rd method they called Chain Tranportation. This method used small vessels to leapfrog from one safe hiding place to another, hiding during the day and running at night until they reached an off-load point. This method failed quickly and the Japanese went back to Rat Transportation.
So much for this long story, which is documented in detail by Richard B. Frank in his book Guadalcanal, an excellent recent history of the battle for Guadalcanal.
ddp59, both of your answers are CORRECT, so you get the next question.
Tom S.