ReHo-44 Orochi

The ReHo-44 Orochi was a Yamataian railway gun developed during the Second Escar-Varunan War. Six guns were produced. The 460 mm guns in the ReHo-44 series had initially been constructed for the fifth Tenzan-class battleship, which had been converted mid-construction into the aircraft carrier Hōshima.

Of the six guns, four participated in Operation Baika against the Yenokaji Line in Chisei, and all four were destroyed in combat. Two were held in reserve and participated in the defence of Hinomoto, where they were captured by the Allies. After the war, the guns were destroyed and sold for scrap by the Chiseian occupational authorities.

As the guns were taken from an Imperial Navy ship, the Navy refused to hand the guns over to the Imperial Army, and all of the railway guns were thus operated by the Navy's SNLF marines.

History
Following the sinking of the battleship Warusawa by land-based aircraft, the Imperial Navy finally began to take the threat of aircraft to warships seriously and hastily ordered the conversion of the final two Tenzan-class battleships into aircraft carriers. Eight of the nine Type-45 460 mm guns made for the fifth ship had already been completed, and the decision was made by the Imperial Navy Land Force to repurpose them as coastal artillery. In mid-1938, the Imperial Army requested to purchase the guns from the Navy in order to create railway guns to support the assault on the heavily-fortified Yenokaji Line in Chisei. The Navy refused to hand the guns to the Army, but implemented the plan and developed the ReHo-44 guns using six of the guns, with the final two used as coastal artillery pieces on Hinomoto.

Completed by December 1938 at Shimokita Arsenal, four of the guns (serials 1 through 4) were sent to Chisei. The final two guns remained in Hinomoto after their transport ship Fukuda Maru was torpedoed by a Chiseian submarine. These guns were requisitioned by the Imperial Navy Coastal Defence Force and were reassigned as mobile coastal guns.

The four guns in Chisei were placed under the 1st Special Artillery Battalion under the SNLF 15th Division (Kaki Heidan), with each battery operating a single gun. The two batteries that did not receive their guns were converted to anti-aircraft batteries. After a few weeks of training, the guns were sent to the front lines against the Yenokaji Line in late May 1939 as part of Operation Baika, providing heavy artillery support. Over the course of the battle, Guns 1, 2, and 4 were destroyed by Chiseian airstrikes. Gun 3 was destroyed after a chamber explosion rendered the weapon inoperable.

The remaining two ReHo-44 guns saw combat during the Allied invasion of Hinomoto, operating under the 7th Coastal Defence Force acting as coastal artillery and later as defensive guns. However, the guns were abandoned after Nibiyama was captured by the Allies. A failed attempt was made to destroy the guns.

Following the end of the war, the Chiseian occupational authorities rendered the two guns inoperable and sold them as scrap metal.