Ametsuchi no Motohashira

八紘之基柱 (Ametsuchi no motohashira), located in the Heiwadai Park (平和台公園), Miyazaki, is a monument to celebrate the enthronement of Emperor Jimmu (神武天皇).  Around 37-meter tall tower was founded in 1940 to proclaim the imperial edict "Hakkoh-ichiu (八紘一宇), inscribed in the facade of the tower in the 2600th anniversary (inscribed in the back of the tower, as well) of the triumph of Jimmu's Eastern Expedition (神武東征). 

The inscribed letters were calligraphed by Yasuhiro, Prince Chichibu,(秩父宮雍仁親王) a younger brother of then-Emperor Hirohito (昭和天皇).

2600 Anniversary in 1940

From the plaque in front of the tower, the tower is also called "Hakkoh-ichiu-no-toh (八紘一宇の塔)". The meaning of 八紘一宇 is translated into "the whole world to be a house" or "all the world under one roof (from English Wiki)", implying the whole nations and people are unified. The word was coined by former Buddhist Nichiren school monk and scholar, Chigaku Tanaka (田中 智學; 1861-1939) in 1903, according to the dictionary, ブリタニカ国際大百科事典-八紘一宇. 

From left to right; Prince Chichibu, Hirohito, Chigaku Tanaka, Fumimaro Konoe. All images from Wiki.

At age 10, he enrolled in Nichiren school as an apprentice to become a monk.  later on, he secularized and became a social and political activist for enlightening so-called "Nichirenism". Since I know very little about Buddhism, all I want to say here is former Buddhist monk coined the word from the article in Shinto Chronicles of Japan, Nihon shoki, complied in A.D. 720 in Nara period. Soon after Emperor Jimmu  subjected indigenous powers dominating Yamato province to Amatsukami's rules, he made a winning statement in the Kashihara. That said.

兼六合以開都，掩八紘而為宇

六合 is an ancient Chinese idiom, meaning a mass/sum (合) of six (六) directions (up and down in the vertical and north, south, east, and west in the horizontal). Collectively, it indicates the universe. Emperor Jimmu and his three older brothers made up their minds to go "East" (Eastern Expedition) from Miyazaki because Miyazaki is too outlying to reign the universe (entire ancient Japan) and Kashihara is the ideal place to be a capital due to geopolitical and agricultural points of view. When he was enthroned as the first Emperor in Kashihara, he proclaimed that Kashihara is the capital of the universe. That is the interpretation of the former part of the sentence, 兼六合以開都.

Inscription of 八紘一宇

In the Chronicle, 八紘而為宇 is the original. 八紘 means "towards the ends of eight (八) corners", indicating the entire world. Note that, as described above, the tower is called "ametsuchi no motohashira". 八紘 (hakkoh) is also pronounced Ametsuchi; Ame and tsuchi mean heaven and ground, respectively, again the combination of two signifies the universe. 為宇 means "regarded (為) as a house (宇)". Altogether, the latter part of the sentence denotes the whole world is regarded as a house. BTW, "而" means "therefore", I guess. Since Tanaka found 八紘為宇 too complicated to make out, he decided to coin the word, 八紘一宇, by changing "為" to "一". In 1903, he submitted an article to the newspaper (国柱新聞) issued by the political organization、Kokuchuhkai (国柱会) founded by Tanaka. In this article, he advocated the significance of the establishment of Japan (= Yamato dynasty) achieved by Emperor Jimmu as the ethical ruling of the universe but not by armed forces. All the existing races, nations, religions, cultures, and customs are to fulfill their own unique nature for harmony as a whole, Tanaka insisted. 

From left to right; Ten cent bill, 10 cent and 4 cent stamps

Unfortunately, owing to Imperial Japan's conflicting circumstances with the world, 八紘一宇 was highjacked as a slogan to agitate for scurrying impetus to the foundation of the Greater East Asia Prosperity Sphere (大東亜共栄圏). It was 1937 when the 八紘一宇 was officially documented for the first time. On the 10th of December 1937, the first Konoe Administration issued the booklet entitled "The spirit of 八紘一宇". Since then the 八紘一宇 as a slogan became so rife that it appeared in 10-cent bills and commemorative stamps. Besides, 八紘一宇 appeared in the lyrics of the Patriotic March. 

往け八紘を宇となし

Onward, east, west, north, and south. Overland and main. Let us make the world our home

四海の人を導きて

Call to fellow men. Everywhere on the four seas

正しき平和を打ち建てん

Let us build the tower of just peace

理想は花と咲き薫る

Let our ideal bloom forth like a flower

Lyrics from Wiki

It is such an irony that Tanaka as a former Buddhist monk has always been against war and insisted on banning the death penalty! Nevertheless, his prudent elucidation of Emperor Jimmu's assertion was exploited by the military and administration of Japan Empire (1867-1947), which culminated in a mournful catastrophe in the sizzling summer of 1945...

To be continued...