Tokkuri in Trinity Square had its front window smashed in the early hours of last Wednesday.
The bar had to shut for one day to clear up and make temporary repairs.
‘It was a thin antique window pane and it just disintegrated and went everywhere,’ said owner Ben Hall.
‘It puts a real dampener on your week, but customers and community have been really supportive. The other businesses sent messages and customers came in especially on Friday to see how we were.’
The bar specialises in sake, Japanese ‘rice wine’, but also serves freshly-made snacks, and Mr Hall said that all of this had to be thrown away.
The bar opened in 2024 and Mr Hall said this was the first anti-social behaviour he had experienced.
‘I think Trinity Square can have an undeserved reputation, but it is actually very quiet, and the pubs and restaurants all support and encourage each other.’
Police said that they were looking for two male teenagers responsible for throwing a small orange traffic light through the window of the bar before running off up Upper Mansell Street, between 12.50 and 1.10am on Wednesday 18 February.
Mr Hall said he had been alerted to the damage by a member of the public and from viewing his own CCTV footage it was clear the damage had been caused accidentally.
‘It was an act of deliberate vandalism,’ he said.
‘Police have taken copies of our CCTV and are doing a sweep of other local businesses.’
Despite the Japanese theme of the bar, Mr Hall is Guernsey-born and bred. He said he became fascinated by sake while working in the more conventional wine trade.
‘The first time I tried it I thought it was awful, but it is as varied as wine,’ he said.
‘I just kept trying it until I discovered reliable and affordable brands I liked and it just went from there.’
n PC171 Harris would like to hear from anyone with further information about the damage on 01481 222 222 or anonymously through Crimestoppers on 0800 555 111.