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"Climb Mount Niitaka"

— A Famous Japanese Code That Many People Have Never Heard Of

Most people have heard the phrase "Tora! Tora! Tora!", the famous radio message associated with the Japanese attack on Pearl Harbor. It has appeared in books, documentaries, and even the classic 1970 war film.

 

But far fewer people recognize another historic phrase that came before it:

 

"Niitaka-yama Nobore" (Climb Mount Niitaka).

 

This was the coded order sent by the Imperial Japanese Navy on December 2, 1941, authorizing the attack on Pearl Harbor to proceed as planned. The full signal was "Niitaka-yama Nobore 1208" ("Climb Mount Niitaka 1208"), with "1208" referring to December 8 in Japan Standard Time—the date the attack would begin in Hawaii due to the International Date Line.

 

The interesting part is that Mount Niitaka was not in Japan.

 

During the period when Taiwan was under Japanese rule (1895–1945), Taiwan's highest mountain, now known as Yu Shan (Jade Mountain), was renamed Niitaka-yama, meaning "New High Mountain." At 3,952 meters (12,966 feet), it was higher than Mount Fuji, making it the tallest mountain in the Japanese Empire at the time.

 

To those familiar with Japanese geography of the era, the phrase symbolized reaching the highest point of the empire. It was a memorable but discreet code that would not reveal military intentions if intercepted.

 

Today, "Tora! Tora! Tora!" is remembered around the world. Yet "Niitaka-yama Nobore" remains a lesser-known piece of history, despite being the signal that set one of the most consequential events of World War II into motion.

 

Sometimes the most famous moments in history begin with words that only a few people recognize.