The Grand Line is not like any other sea. Its magnetic fields twist wildly, weather shifts without reason, and islands themselves warp compasses into madness. To survive, sailors must rely on Log Poses — and to uncover the world’s true history, they must seek the Poneglyphs.
Together, these artifacts represent both the path forward and the weight of the past.
Magnetic compasses do not function on the Grand Line, where islands emit unique magnetic fields. The only way to sail is with a Log Pose:
Single Log Pose – Locks onto one island’s magnetic field, then adjusts to the next.
Eternal Pose – Permanently set to one island, never changing. Rare and coveted.
Multi-Log Pose (later versions) – Can lock onto multiple magnetic routes, offering choice of destination.
⚓ Rule of the Grand Line: Sailors must follow the Log Pose’s pull until the island’s field “sets.” Only then can it adjust toward the next island.
Scattered across the world are massive, indestructible stone blocks known as Poneglyphs, carved with a script lost to time. They are remnants of the Void Century, forbidden history erased by the World Government.
Historical Poneglyphs – Contain records of ancient events.
Instructional Poneglyphs – Lead seekers toward others, guiding the path.
Rio Poneglyph – Said to combine all truths into one complete record.
Road Poneglyphs – Four unique stones that, when deciphered, reveal the path to the final island: Raftel (Laugh Tale).
Only a handful of people, such as the scholars of Ohara and Nico Robin, can read them. The World Government forbids their study, declaring it a crime punishable by death.
Calm Belt – Windless seas bordering the Grand Line, swarming with Sea Kings. Only ships with Seastone keels or massive power can cross.
Wild Weather – Storms, whirlpools, and lightning strike without warning.
Island Climates – Each island has a unique and stable climate, often extreme, set by magnetic currents.
Sea Charts – Nearly useless in the Grand Line unless paired with Log Pose routes.
Whale Markers – Travelers and pirates sometimes mark dangerous currents or hidden passages on massive creatures or reefs.
Eternal Poses – Rare treasures for merchants and governments, used to secure steady trade routes.
The Road to Raftel – Only by reading the four Road Poneglyphs can one find the Pirate King’s final destination.
The Void Century – The Poneglyphs preserve truths the World Government desperately erases.
Inherited Will – Some claim the stones themselves are part of a greater destiny.