1. First Black Coin
Get on the springboard, latch on the two Surprise Question Blocks with a Ninji on top of it. Then make a high jump to the right to get the first Black Coin.
2. Second Black Coin
Jump past the springboard and then drop to the lower platform in the airship since the second Black Coin is located there.
3. Third Black Coin
After moving past the airships filled with several Rocky Wrench dudes, jump to the lower airship with a Surprise Question Block and then bounce off on that block to latch on the wall of the higher airship and slide down to get the third Black Coin.
4. Fourth Black Coin
Get on the row of Surprise Question blocks with a Ninji walking on top of it and then make a big jump to the right to get the fourth Black Coin.
5. Fifth Black Coin
To get the fifth Black Coin, continue moving forward until you find a series of floating platforms with some Rocky Wrench foes on top of these platforms. On the third platform, make a high jump to the right to get the fifth Black Coin.