The First Cave
Once you set foot on Catwald Island you will see a road, following this road leads to a cave and a locked town. . You will need to know ~330-340 kanji to be able to make it through this cave. At the end of the cave is a treasure chest with a key and a set of stairs. The key unlocks the first town. The stairs lead to an endless hallway.
Once you unlock the First Town you can enter it. To complete the First Town you need to know about ~380-390 Kanji. In order to complete a town you must simply pass from one end of the town to the other. The remaining towns don't have a locked door and you don't need a key to get into the towns. To complete the Second Town you need to know ~400-410 Kanji. To complete the Third Town you need to know ~430-440 Kanji. The Fourth Town contains several treasure chests filled with: various items, the sea lantern, and the tent. There is also a house with a bed to sleep in. To complete the Fourth Town you will need to know ~450-460 Kanji. To complete the Fifth Town you will need to know ~480-490 Kanji. The Sixth town is like a maze and it is easy to get lost. To complete the Sixth Town you need to know ~500-510 Kanji. To complete the Seventh Town you will need to know ~570-580 Kanji.
The Last Cave
To complete the cave you will need to know ~620-630 Kanji. At the end of the cave you will find a treasure chest, and a set of stairs that lead to another endless hallway. In the chest is something called a complication, which is actually the chronolabe. Take the chronolabe to the sage.