Nestor Cerpa, alias Comandante Evaristo, was wearing black military boots when he led 15 Tupac Amaru guerrillas up a fire escape into the Japanese ambassador's residence on 17 December. Now he either goes barefoot or wears sandals. He's hooked on sushi and does Japanese aerobics daily to the sound of a taisa cassette.
There are believed to be more than 24 Japanese businessmen, plus their country's ambassador, in the occupied building. In the days after the assault, neither Mr Cerpa nor his comrades, including two teenage girl guerrillas, understood a word of Japanese. Now, the Japanese among the 72 remaining hostages call him "Cerpa-san", according to Red Cross doctors who have witnessed the transformation.
Cerpa-san first demanded sushi to make his Japanese "house guests" feel at home, but he himself is now said to enjoy raw fish at least once a day.
Cerpa-san stacks his Chinese-made rifle against a wall before morning exercise. But his 17-year-old female comrade Jobana, known by her nom de guerre Saida, keeps hers strapped across her back while stretching, the doctors say.
Bored after almost four months together, guerrillas and hostages are said to be giving each other language lessons to while away the time. The interpreter? President Alberto Fujimori's younger brother Pedro, who learnt Japanese from his parents.