Like many of his Japanese compatriots, his knife skill is likely among the best in the world.

But it's the ingredients he's using which could yet bring down the curtain on his eight-year-old restaurant in the Chinese capital Beijing.

(SOUNDBITE) (Japanese) 49-YEAR-OLD JAPANESE RESTAURANT OWNER, KAZUYUKI TANIOKA, SAYING:

"The hardest thing for us now is that we can't purchase any Japanese seafood at all because it's taking so long to clear Chinese customs due to the treated radioactive water release issue."

Like most Japanese restaurants in China, Tanioka's outlet Toya imports fish from Japan.

But Chinese restrictions on some of those imports are making business harder.

Shortly after the 2011 tsunami and earthquake damaged the Fukushima nuclear plant in Japan, Beijing banned food and agricultural products from five Japanese prefectures.

That ban was later widened, and now covers 10 of Japan's 47 prefectures.

The latest restrictions were brought in as Japan plans to empty into the sea treated radioactive water from Fukushima - a move endorsed by the United Nations' nuclear watchdog, but sharply criticised by China.

(SOUNDBITE) (Japanese) 49-YEAR-OLD JAPANESE RESTAURANT OWNER, KAZUYUKI TANIOKA, SAYING:

"Since around mid-July, with the planned release of treated radioactive water, the number of Chinese customers has slid around 90% due to worries about Japanese food ingredients."

Imports have since all but ground to a halt, with some Japanese officials fearing the worst is yet to come.

While more stringent Chinese checks have led to massive delays at customs, the bigger worry is what consumers are saying.

Posts and hashtags on Chinese social media claim Japanese food is radioactive and should be boycotted.

This customer said he was reassured by the steps China had taken, calling it a "responsible attitude."

But some say when it comes to Japanese food, there are misconceptions about what is and isn't safe.

67-year-old Japanese restaurant owner Kenji Kobayashi.

(SOUNDBITE) (Japanese) 67-YEAR-OLD JAPANESE RESTAURANT OWNER, KENJI KOBAYASHI, SAYING:

"I don't know about the Fukushima water release in much detail, but if you have a look, you'll find other places are doing the same thing, releasing things into nature. The fact that the average person just doesn't know this - this is the hardest thing. If they knew about it, then they would know they could eat safely."

Japanese officials have appealed to their Chinese counterparts, especially in their second-largest market Hong Kong, to avoid a ban.

Some importers have meanwhile said they're considering shipping their product through a third country.

Chefs like Tanioka have said they're now looking at sourcing ingredients from inside China to survive.

And while even with the restrictions, China remains the largest importer of Japanese seafood, if these problems continue, that may not be the case for much longer.