Complete the checklists at the starting menu and side mission memo pad lists to unlock the following items.

Best Dachi in the Realms (Tenka no Dachi): Skills list
Dragon Chestplate: Weapons list
Ganryuu Bokutou: Arena Opponents list
Immortal Turtle: Yuujo (Pleasure District girls) list
Lucky Beads: Storage Lockers list
Meow Shoes: Inventions list. Talk to Gyoutensai to get the shoes.
Peerless Wakizashi (Musou no Wakizashi): Memo Pad list
Seven Luck Dieties Sarashi: Food and Drink (restaurant menu items) list
Skanda Shoes: Skill Games list
Ultimate Badge: Heat Actions list