Kaigun Rikusentai means Naval Landing Force in Japanese. The term (often shortened to just Rikusentai) has been used to describe sailors organized into temporary ground combat units from ship crews since the Meiji Era. In the early 20th Century the Imperial Japanese Navy began to create semi-permanent ground based units independent of ship crews, such as Tokubetsu Rikusentai Special Naval Landing Forces and Keibitai Guard Units, which would see significant action in the Second Sino-Japanese and Pacific Wars.
History of Naval Landing Forces in the Showa Era
February, 1927 - Naval Landing Forces are dispatched to Shanghai, the Shanghai Naval Landing Force is soon created.
January 28, 1932 - First Shanghai Incident begins, the Shanghai Naval Landing Force participates with help from nearby ship crews, nearly arrived battalions of troops from the Naval Districts, and the Imperial Japanese Army.
October 1, 1932 - The Shanghai Naval Landing Force is renamed to Shanghai Special Naval Landing Force (Shanghai SNLF), making the first officially recognized SNLF unit.
October 15, 1936 - Naval District Special Naval Landing Forces are added to the Tokusetsu Kansen Butairei Specially Designated Vessel Unit Decree.
July 7, 1937 - The Second Sino-Japanese War begins with the Second Shanghai Incident, the Shanghai SNLF and several new SNLF battalions fighting in the city. Nearly twenty SNLF units participate in operations throughout China between 1937 and 1941.
January, 1938 - The 1st Combined SNLF supported by additional independent SNLFs capture Tsingtao and occupy the city.
May, 1938 - The 2nd Combined SNLF invades and takes control of the coastal city of Amoy.
February, 1939 - The 4th Base Force with three SNLF battalions under its command captures Hainan Island.
November 15, 1939 - Most of the Naval Landing Forces in China are reorganized into Special Base Forces and Base Units.
July 31, 1941 - The first six Guard Units are formed.
November, 1941 - The Kaigun Keibitai Naval Guard Unit decree is passed, Naval Guard Units are established at the four Naval Districts.
Dec 8, 1941 - The Pacific War begins, SNLF units soon invade the Philippines and Wake Island.
March 10, 1942 - Most of the active SNLF units are disbanded and used to create occupational Guard Units and Special Base Forces. A new generation of SNLF units soon follows.
November 20, 1942 - The 8th Combined SNLF is created to defend the Solomon Islands.
December, 1942 - A new type of Naval Landing Force known as Bokutai Air Defense Units are introduced to the IJN. Approximately 162 units would be formed over the next two years.
April, 1943 - The Allied Salamaua–Lae campaign begins, Guard Units and SNLFs along the eastern coast of New Guinea are continually pushed further north as they struggle to hold territory.
November, 1943 - The 3rd Special Base Force, Sasebo 7th SNLF, and several other units garrisoned in the Gilbert Islands are almost entirely annihilated in one of the deadliest defeats the Imperial Japanese Navy has suffered yet.
February, 1944 - The 6th Base Force's headquarters and subordinate units including the 61st Guard Unit are destroyed during the Battle of Kwajalein as Allied Forces capture the Marshalls and move towards the Marianas and Philippines.
June, 1944 - The Yokosuka 1st SNLF is destroyed on Saipan, marking the last SNLF unit to be destroyed in combat. The 6th Fleet Headquarters and the 5th Base Force on Saipan along with its subordinate units on Saipan, Tinian and Guam are destroyed.
July, 1944 - The Imperial Japanese Navy begins to form additional Naval Guard Units across Japan for homeland defense.
October, 1944 - Allied Forces begin to retake the Philippines. Naval ground units garrisoned throughout the archipelago would participate a massive defensive campaign until the conclusion of the war.
January, 1945 - The Yokosuka 8th SNLF, the final new SNLF to see action outside of Japan, is formed.
May, 1945 - Allied Forces launch a campaign to recapture Borneo. Special Base Forces and Guard Units garrisoned throughout the East Indies fight to maintain control with the help of local volunteers.
June, 1945 - The Okinawa Area Base Force and many of its subordinate units are destroyed during the Battle of Okinawa.
July, 1945 - Naval Districts and Guard Districts across Japan begin to form Combined SNLFs in anticipation of home defense.
August 15, 1945 - Japan surrenders. The Imperial Japanese Navy remains operational for administrative purposes for the following months while Naval Landing Force units are gradually disbanded and repatriated. Despite the surrender, a few units engage against Soviet forces.