The invasion of Niigata was a large-scale incursion by a BETA herd from the Sadogashima Hive into central Honshu, Empire of Japan on November 11, 2001. It was the second invasion of its kind by the BETA, following an earlier invasion of the region in February of the same year.
A curious aspect of this battle amongst the rest was the BETA's strategic movement. Instead of charging at opposing forces straight on, the BETA chose to engage in evasive tactics and diversionary movements.
History[]
Unlimited/The Day After[]

Initial BETA advance from the Sadogashima Hive.
The BETA advance was detected by Japanese forces at 06 20 hours when their movement brought them out of the Sadogashima Hive and into the surrounding waters. The brigade-sized BETA herd then made their advance southwards, towards the Niigata prefecture.
By 06 27 hours, the BETA herd had advanced beyond the Primary Ocean Defense Line held by the warships of the Imperial Navy's 34th, 55th and 56th Naval Squadrons. Destroying the 56th Naval Squadron, the BETA surfaced on the shores of Niigata as three concurrent hordes at 06 48 hours, and were met and encircled by the 104th, 132nd, 137th, 189th, 195th, 206th, 208th, 231th, and 225th Squadrons from the IJA/MDF's 12th Division on the old national highway.
The 12th Division failed to secure victory and suffered losses with the total annihilation of the 104th, 189th, 195th, and 231th by 07 10 hours. Reinforcements from the 14th Division were late, and by 0729 the BETA had pushed into the mainland; contact with them was lost soon after as the BETA had dispersed into the lands and the 14th Division was unable to pursue them.

The last phase of combat against the Niigata Invasion.
At 08 07, the BETA regrouped and broke through the Seconday Defense Line, advancing to a south-west point within 10 kilometers of Mout Hakkai. Skirting southwards along the Final Kanto Defence Line, the herd switched position again, bringing the entirety of the horde, vanguard, main body, and stragglers southeast through the Niigata, Nagano and Gunma prefactures. The horde changed directions one last time to face Yokohama Base directly at 08 33 hours, this time clashing with pursuing IJA/MDF troops of the 5th and 7th Divisions at the Final Kanto Defense Line.
As a result of this final push, the United Nations' Yokohama Base brought its alert levels to DEFCON 2, setting all active, auxiliary and training personnel on standby. The UN's 404th Tactical Armor Battalion was also activated at Atsugi Base and sent as reinforcements to the IJA/MDF troops at the Final Kanto Defense Line.
Yokohama Base was finally released from DEFCON 2 alert status at 11 23 hours when the BETA horde was finally annihilated by IJA/MDF/UN forces.
Alternative[]
In Alternative, the exact same events happened up to the the 12th Division's engagement with the BETA horde. Joined by reinforcements from the 14th Division at 07 10 hours, the BETA were held off at the Chuetsu and Kaetsu Provinces, and their main force broken. Yokohama Base still activated its personnel for DEFCON 2 status until the destruction of all BETA from the advance had been confirmed.
Aftermaths[]
Unlimited/ The Day After[]
The BETA's advance in this version of the Invasion of Niigata wrought destruction far and wide in both military and civilian assets and personnel, with the horde nearly crossing the mainland to reach Yokohama Base.
Alternative[]
With Shirogane Takeru's forewarning, the hard-fought battle in the Unlimited universe was adverted, and the BETA were easily destroyed with much less loss of manpower and infrastructure.
With knowledge of this attack, Kouzuki Yuuko deployed Special Task Force A-01 to Niigata for her own reasons. Their clandestine involvement in the operation allowed them to capture many BETA specimens; these same specimens would later be involved in the Yokohama Base Incident.