A Japanese artist who made a kayak modelled on her vagina has denied obscenity charges at the start of her trial in a case that has drawn accusations of censorship and double standards.

Megumi Igarashi, who calls herself Rokudenashiko – which roughly translates as good-for-nothing girl – was first arrested last July after distributing digital files containing a 3D scan of her genitalia to people in return for donations to her project to create the unusual artwork.

She was released days later following a public campaign supporting her right to freedom of expression. She was rearrested in December, however, and charged with obscenity.

The 43-year-old artist told the Tokyo district court on Wednesday that her “vagina selfies” were not obscene. “I do not dispute the facts [of the charge], but my artwork is not obscene,” Igarashi said, according to the Kyodo news agency.

Defence lawyers will argue that using the penal code to punish obscenity violates Igarashi’s constitutional right to freedom of expression. “Even if it were not constitutional, the defendant’s work is not a precise reproduction of the vulva and does not cause sexual arousal,” Kyodo quoted a defence counsel for Igarashi as telling the court.

If found guilty, Igarashi could face up to two years in prison or a maximum fine of 2.5m yen (£14,200) for distributing obscene objects.

She is accused of distributing data to people in return for donations to the crowd-funding kayak project. The recipients could use the data to print 3D images of her genitalia.

Her vagina-inspired artworks were also exhibited at a sex toy shop in Tokyo, according to the indictment. The 44-year-old owner of the shop, Minori Watanabe, was arrested and ordered to pay a 300,000 yen fine.

Igarashi said she had sent the data to people who had donated more than 3,000 yen to the kayak project. She said she was prepared to take her case all the way to Japan’s supreme court if necessary.

Igarashi has made a name for herself with her Decoman “Decorated Vagina” series of sculptures. The titles of the works incorporate the word “man”, from manko, the Japanese slang for vagina.

Her case has attracted worldwide attention and criticism of the apparent double standards in the Japanese law’s treatment of sexual imagery. While the country has a thriving pornography industry, its obscenity laws ban the depiction of genitalia, which usually appear pixelated in images and videos.

Commentators pointed out the hypocrisy of her initial arrest, which came soon after Japanese authorities resisted pressure to ban pornographic images of children in manga comics and animated films.

Watanabe, who writes under the pseudonym Minori Kitahara, said at the time: “Japan is still a society where those who try to express women’s sexuality are suppressed, while men’s sexuality is overly tolerated.”

Igarashi has said she wants to use her art to “demystify” female genitalia in Japan, where 3D images of male genitalia draw thousands of visitors to the Kanamara penis festival at a Shinto shrine in the city of Kawasaki, near Tokyo, every April.