The Shogunate of Falklandia, known as Falklandia, is a Military Stratocracy masquerading as a Republic. The government of Falklandia is similar to the old British state, following the Westminster parliament, with a House of Lords and a House of Commons. However there is no Prime Minister, the Shogun taking over that role. The House of Lords also has little power, their votes merely a formality. The Monarch as well also has no power.
Reginald Knight was, by every definition, an insane man. Having left home at a young age he ended up in Japan and stumbled through the language eventually becoming able to speak it. He was dismissed as a madman by most, but some were entertained by him, and he learned many things, even Japanizing his name. Eventually with the end of the Anglo-Japanese Alliance it was decided that it would be unsafe for him to remain in Japan and with a heavy heart he departed for Britain. While in Britain he took on odd jobs and got extremely lucky with investments, eventually becoming extremely wealthy. He used his wealth to continue his obsession with the Japanese, eventually moving to the Falklands.
With the outbreak of WWII, he joined the local garrison and donated his money to fund the local defenses. He personally funded the supplies of the island and the repairs of the ships in the region. Due to his service to the crown, he was appointed Governor of the Falklands Islands in 1941 and took command of the garrison. With the end of the war in Europe he began working on attracting immigrants, mostly former soldiers, expanding the garrison and forming his own mercenary company. Then in 1955 the best possible scenario for him happened, the government of Juan Perón was couped in Argentina. Seeing the potential for this he launched an invasion of Argentina, nominally to support Perón, but really it was to serve his own interests. While the rest of the world was distracted with Japan Peronist and Falklander forces worked together to wage a civil war that ended with a Falklander-Peronist joint victory.
Distracted by the events in the Pacific the UK government gave their blessing to form a new dominion, officially establishing Falklandia as a nation. This is where the insanity that had been bubbling underneath the surface burst forth. Declaring himself Shogun he formed the Shogunate of Falklandia and began establishing a government, backed by his own wealth and military force. While shocked the Peronist forces had no choice but to follow in his footsteps, having been severely weakened by the civil war. The next several decades showed that while he may have been insane, he was at least good at appointing the best people to their positions, leading everyone to humor him until it was finally too late.
Come 2100 Falklandia has been mostly anglicized. Cities have been renamed to English and is the main language spoken, with Spanish words being used as well. The population has accepted the current state of affairs and the nation is shockingly stable. While some resent the government, a majority see it as competent, if weird.