The Maisaka region in Nioh 3 has only one Six Jizo Statue, and it's one of the trickier ones to complete. Unlike most Six Jizo locations, where you simply walk up and pray, this statue near the Water Mill Shrine is missing a head. The game won't let you interact with it until you find the missing piece and physically carry it back.
Quick answer: While facing the Six Jizo Statue, look to your right. The stone head is sitting on top of a large rock platform that you can reach with a double jump. Pick it up, carry it back to the statues, and place it to complete the interaction and earn 50 Jizo Merits.

How to reach the Six Jizo Statue in Water Mill
The Six Jizo Statue sits across a body of water from the Water Mill Shrine. You can't simply walk over to it — you need to first activate a lever located to the right of the shrine. Pulling this lever lowers a drawbridge (or dam mechanism), which drains enough water to create a crossable path.
Once across the bridge, head up the hill toward the statue. There are a couple of dangerous enemies along the way. A Yokai perches on top of a rock near the path, and a water creature lurks further ahead. A Crucible Wraith may also be in the area, so approach with caution and clear enemies before attempting anything else. You need the area relatively safe because carrying the head back leaves you vulnerable.

Finding the missing Jizo head
When you reach the Six Jizo Statue and try to pray, the game tells you something is missing. The missing head is extremely close by — you don't need to explore further into the area or lower the water level again to find it.
Step 1: Stand directly in front of the Six Jizo Statue and face it.
Step 2: Turn to your right. You'll see a large rock platform nearby. There's also an enterable house in this area with loot inside, but the head isn't in there.
Step 3: Double jump onto the rock. The stone Jizo head is lying on top of it in plain sight.
Step 4: Pick up the head and carry it back to the statues. When the prompt appears, place the head on the statue.
Once the head is restored, you can pray at the Six Jizo Statue and collect your Jizo Merits. Successfully praying rewards 50 Jizo Merits, which can be spent at any Shrine under the Blessings menu to unlock Jizo Blessings — buffs that specifically improve your survivability inside Crucible areas.

Don't get hit while carrying the head
This is the part that catches people off guard. While you're holding the stone head, enemy attacks will interrupt you and potentially knock the head out of your hands. If enemies are still aggro'd or chasing you, they'll make the short walk back to the statue far more frustrating than it needs to be. Clear out every nearby enemy before you pick up the head. The Crucible Wraith in particular can be ambushed with ranged weapons before you close in with fast attacks.
Finish draining Water Mill before you leave
After completing the Six Jizo interaction, don't leave the Water Mill area immediately. On the opposite side of the dam from where you entered, there's a second lever. Activating it fully drains the remaining water from the mill area, revealing a ladder you can descend.
At the bottom, you'll find lootable corpses and a path leading to a torii gate on a small island. Cross over to a cave entrance where another Crucible Wraith fight awaits. Defeating it and looting the cave clears the area completely. This cave contains a Lesser Crucible, one of the game's tougher optional combat encounters that rewards valuable gear.

Why Six Jizo Statues matter
Six Jizo Statues are scattered across all three time periods in Nioh 3 — the Warring States (1572 CE), Heian (1190 CE), and Bakumatsu (1864 CE) eras. There are 20 total across the game, and praying at all of them unlocks the Visiting the Six Jizo trophy. More practically, the Jizo Merit currency that the statues provide funds Jizo Blessings at Shrines. These blessings stack incrementally, and all apply specifically to Crucible zones, where enemies deal more damage and can inflict Life Corrosion. The percentage boosts start small but become meaningful as you accumulate more.
Not every statue is a simple "walk up and pray" situation. Some require a monetary offering, others involve finding a missing head like the one in Maisaka, and at least one in the Bakumatsu period hides its head inside a Mimic Chest. The Maisaka statue is one of the earliest headless variants you'll encounter, making it a good introduction to the mechanic before the later, more complex versions.