Short answers, pulled from the story.
Operation U-Go was the Japanese invasion of India in 1944 that began on the 6th of March 1944. The offensive aimed to capture Imphal and Kohima but failed due to logistical weaknesses and Allied countermeasures.
Lieutenant-General Renya Mutaguchi commanded the Fifteenth Army during Operation U-Go. He ordered fresh attacks until late June when his forces proved unable to obey commands due to starvation and disease.
Japan suffered 60,643 casualties including 13,376 dead during the entire operation period of Operation U-Go. Most losses resulted from starvation, disease, and exhaustion rather than direct combat casualties.
The Battle of Kohima took place in two stages from the 3rd of April 1944 to the 16th of April 1944. A small British force relieved the ridge on the 16th of April while newly arrived Indian XXXIII Corps counter-attacked driving Japanese from captured positions.
Subhas Chandra Bose led Azad Hind Fauj or Indian National Army which joined attacks on Imphal from south and east at his insistence. Two brigades from the INA originally intended as auxiliaries for reconnaissance and propaganda purposes participated in the offensive.