nhk's takeshi togawa reports. >> reporter: citizens are appealing for democracy and freedom of speech on the internet. >> reporter: these images were taken by chinese artists. he has interviewed more than 400 people so far. >> translator: our society has problems. through my interviews, i want to clarify whether they are systemic or human problems. >> reporter: he was a university student at the time of the tiananmen square incident. he joined pro democracy movement and witnessed firsthand how the government shut up citizens' voices with force. yang wants to see a democratic society in china. he's using his camera to capture and spread the voices of people. in addition to his internet postings, he has put some books together to reach out to as many people as he can. he used publishers in hong kong since he couldn't put them out in mainland china. but the government pressure remains strong. this woman is a prominent journalist. yang interviewed her in the past. like him, she campaigned for freedom of speech, but she was detained by authorities last year. she received a seven-year priso