The Northwest Passage is the hoped-for water route joining the Pacific and Atlantic, imagined as a passage from the Californias to Newfoundland through the Straits of Anian. In John Blackthorne’s story it is at once a geographical mystery and a measure of maritime ambition: no one has proved it exists, yet the search for it promises to redraw the known world.

The Route and Its Uncertainty

The route is presented as a legend still awaiting proof. As a boy, Blackthorne hears that an expedition might sail through the Strait of Magellan, travel up the coast toward the unexplored Californias, and search for the Straits of Anian. If those straits joined the Pacific to the Atlantic, the route would continue toward Newfoundland and finally establish the Northwest Passage. The sequence offers a bold prospect, not a confirmed geography: Blackthorne’s master, Alban Caradoc, emphasizes that no one has yet proved the supposed passage.

The uncertainty belongs to the larger problem of navigation. Charts are so vague as to be nearly useless, and navigators have no way to determine longitude. Far from land, a ship cannot reliably fix its position by chart or calculation alone. A route across unknown waters is therefore not just a matter of courage or a favorable wind; it depends on accumulated knowledge that can guide a pilot where the coastline offers no familiar landmarks.

Rutters, Pilots, and Control of Knowledge

A rutter supplies one practical answer to that uncertainty. It is a small book of a pilot’s observations, recording compass courses between ports and capes, water depths and color, seabed conditions, winds, currents, storms, safe anchorages and places to replenish water. Its value lies in particulars: it preserves how a ship reached a place and how it might return. Such a record could make a dangerous, unfamiliar sea more legible, but it could not make its information infallible. Rutters might contain copying or translation errors, even deliberate ones, and a pilot could not be certain of a route until he had sailed it himself.

The Northwest Passage thus sits within a contest over access to maritime intelligence. English, Dutch, and French pilots possess rutters for their own waters, while Portugal and Spain guard the records of routes through the wider world as national secrets. Information about the Strait of Magellan, the Cape of Good Hope, and the sea routes onward to Asia is treated as strategic property, coveted by their northern rivals. The quest for the Northwest Passage would require not only a ship willing to enter unknown waters but access to knowledge that Portugal and Spain seek to keep from their competitors.

Blackthorne’s Early Ambition

At thirteen, Blackthorne wants to join an admiral’s expedition and help become the first English crew to pass through the Strait of Magellan and enter the Pacific. The Northwest Passage gives this proposed voyage its farthest horizon: from the Californias, the expedition would press north in search of a connection to the Atlantic. His urgency reflects the possibility that the expedition could be a once-in-a-lifetime opening; Caradoc counters it with the discipline of a pilot, insisting that a navigator must learn patience. He also warns that reaching Magellan’s route would require stealing a rutter or capturing a Portuguese pilot able to guide the expedition through it.

Blackthorne’s ambition is sharpened by the return of Francis Drake’s circumnavigation. Drake’s Golden Hind comes back after three years with immense treasure, and the Queen knights him; investors profit and sailors compete for a place on his next voyage. Yet the expedition has lost four of its five ships and eight out of every ten men, and it has failed to find the Northwest Passage. A captured Portuguese pilot had guided Drake through the Strait of Magellan into the Pacific. The celebrated voyage therefore demonstrates both the rewards of oceanic exploration and the human cost and limits of an expedition that still cannot prove the northern route.

Navigation Beyond the Legend

Later scenes make the pilot’s work concrete without turning the Northwest Passage into a discovered route. During a voyage along the Izu Peninsula, Vasco Rodrigues takes a galley south along the coast, then sets a west-southwest course from Cape Ito toward Cape Shinto, about two hundred miles away. He chooses open water because a coastal route would take too long. The episode distinguishes coastal skill from ocean navigation and shows how a decision about course and time can determine a journey’s risk.

In another dangerous passage, John Blackthorne judges how a frigate must tack near cliffs and a harbor mouth, where there is little sea room between success and disaster. These practical acts of navigation echo the earlier problem of the Northwest Passage: sea power depends on knowing routes, winds, and the handling limits of ships. But the contrast remains decisive. Blackthorne can read a course and maneuver vessels in known waters; the passage he dreamed of as a boy remains unproved.