Note: items are listed in order of gameplay.

Raizan (Shiden) can be found in Underground Temple in the same with 6 blue porcelain jars, along the way near the exit on the opposite site of the Underground. It is obvious if you did not see it on your way. See: Part 1: Reunion and Separation

Enryuu (Kouen) is one of the strongest weapons after Bishamon Sword but also the heaviest weapon to wield. After killing Boss Osric, continue the hallway until you reach a dead-end with a room. In there, you can it up in the room after a cutscene. You cannot miss it though as you needed it to exit the building. See: Part 2: The Keep

Inside the Keep, next to the main hall. See: Part 3: Trap, Trap, Trap!

Bow is the first long range weapon you get, it is located in a room under a staircase inside a puzzle box. After watching a cutscene with boy and Kaede, proceed to the next room, you will find the staircase. You can use the bow to fire normal or fire arrows. But, there is no fire arrows as an item so you have to enhance normal arrows using souls at Magic Mirror. See: Part 3: Trap, Trap, Trap!

Solution: left, right, left, right, right

Inside a room with a staircase after you opened a sealed room with level-1 fire crystal, second floor of the Keep. Another one is right next to the staircase after you go up. See: Part 3: Trap, Trap, Trap!

Holy Armor is missable if you are not careful enough when unlocking the hallway trap with Kaede. Here is a list of steps to unlock the treasure box containing Holy Armor:

• Step 1: there is only one lever, pull it up.
• Step 2: move Kaede to pull the right lever.
• Step 3: move Sam to pull another. It will trigger to open another section.
• Step 4: This section has 3 levers, move Kaede to pull the far left. 

See: Part 3: Trap, Trap, Trap!

After you encountered a Three-eyes performing a jump scare when you cut paper screens, you will see a staircase. Next to the staircase is a treasure box with the arrows. See: Part 4: Rescuing the boy

Shippuu (Arashi), your third weapon with wind element can be obtained by defeating a boss Marcellus on a rooftop. Well, it is very dramatic though, haha. See: Part 4: Rescuing the boy

It is located inside the room where you rescued the boy. Unfortunately, you cannot open it yet because of the cutscene. Well, after the cutscene, you will have to walk all the way back to that room again, what a nuisance. If you follow my walkthrough, you should have unlatched a back door to a room sealed with level-2 fire crystal. Then, you can just follow the map below. Also see: Part 5: Keep Underground

It is located in the west garden on the grass. Along the way, you will see a flickering object on the ground. See: Part 6: Found the Princess

After you open the door with Silver Plate and Gold Plate, you will find yourself in a burning hallway. The room to left right after you appear is where the Sacred Knife is in. It is on the second floor inside a puzzle box. See: Part 6: Found the Princess

Solution: mid, right, right, left, left

At the end of the burning hallway. See: Part 6: Found the Princess

This Burst Bullets is missable because it requires you to help a soldier while on your way to pick up Decorated Sword. Basically, you need to kill all Zombie Warriors and Zombie Archers, then he will drop the Burst Bullets. See: Part 8: From West to East

Inside a red treasure box on the yard where you defeated mini-boss Barabazuu (a red giant ogre) with his 3 minions. See: Part 8: From West to East

Matchlock is the second long range weapon you can get in the game, it is highly effective against flying monsters especially Hecuba (boss). After you defeated the giant red ogre, pick up Statue Head in a treasure box then head back to the room sealed with level-3 blue crystal. Put the statue Head back on the Buddha statue to disable a trap behind the room. Inside the chest is Matchlock. See: Part 8: From West to East

First Bullets can be found in a treasure box after you dropped a drawbridge. 

Second Bullets is in a room on the other side of the passage after you picked up Journal #6; you will run pass a Samurai on the passage and ignore the first door.

Third one is in the building (the first door) in front of the Samurai.

See: Part 8: From West to East

Great Armor is the last and strongest armor of the game. It is located behind the waterfall of the east garden; the area with a swing bridge and 2 Samurai. You will have to solve a puzzle as well. See: Part 8: From West to East

Solution: bottom-left, top-right, bottom-right, bottom-left, bottom-right

When playing Kaede as a second time, between the first and second doors you unlocked is another passageway that lead to a red treasure in the corner. See: Part 9: A Helpful Partner

The storage house (Magic Mirror and Magic pool inside) at the waterfall, unlock the other door with your Shinobi Kit. It is behind two wood barricades. See: Part 9: A Helpful Partner

Bishamon Sword is the ultimate weapon because of the enemies die in one hit (it's boring I know). Unfortunately, it can only be obtained at the end of the game and has to go through 20 floors of the Dark Realm to get the key. It is in the save room after you defeated Marcellus (second encounter). In there, use Bishamon Ocarina to open the door. 

There is another way to use Bishamon Sword from the start of the game by collecting all Fluorites (to unlock Oni-spirits), complete Oni-spirits mini-game (to unlock Ultimate mode), then play the game in Ultimate mode.

See: Part 10: Enter Demon World

In a room full of blue porcelain jars, underneath one of them is the Kunai (the one to Kaede's left hand when she first appears). See: Part 9: A Helpful Partner