Everyone in Japan remembers the American aircraft carriers and helicopters that flew across the sky during Operation Tomodachi in March 2011. Almost nobody knows about the Americans who crawled across the pitch-black bottom of the freezing ocean so northern Japan would not freeze to death. After the tsunami of March 11, snow was falling across northern Japan. Tens of thousands of survivors in shelters had no electricity and were running out of kerosene for their heaters. Japanese fuel tankers loaded with heating oil were waiting offshore, but they could not dock. Why could the fuel ships not enter the harbors at Hachinohe and Miyako? Because the tsunami had swept thousands of cars, semi-trucks, tangled fishing nets, and crushed houses onto the harbor floor. If a fuel tanker tried to enter, submerged steel wreckage would rip open its hull. And surface cranes could not simply scoop the debris out blindly because heavy fishing nets and steel beams were tangled together on the bottom in thirty-six-degree water thick with black fuel oil and silt. You could not see one inch in front of your face underwater. That was when the U.S. Navy sent in Underwater Construction Team Two and Mobile Diving and Salvage Unit One. Wearing sixty-pound diving helmets and heavy rubber drysuits to keep out the toxic oil and chemical runoff, young American Navy divers stepped off snow-covered piers into the freezing black water. Down on the harbor floor in total darkness, where a single jagged piece of car metal or a shifting truck could trap a diver or slice his air hose, the Americans worked entirely by the touch of their gloved hands. Inch by inch, feeling their way across crushed family cars and twisted steel cables in thirty-six-degree water, they cut the wreckage apart with hydraulic saws and hooked crane cables to hundreds of tons of debris until the shipping channels were clear. When the first Japanese fuel tanker finally glided safely into port bringing heat and light back to the freezing towns, the American divers just washed the black oil off their suits and moved to the next harbor. True allies do not just stand beside you in the sunlight. They dive into the freezing dark where nobody is watching.