I recently found a trio of interesting Japanese products at City'super (Times Square, Causeway Bay, tel: 2506 2888).
Shio koji is being touted as the hot new ingredient in Japanese cooking, and it's crossing over into other cuisines, too. Made of shio (salt) and koji (an edible mould used for many Japanese fermented products, including sake, miso and soy sauce), shio koji gives savoury food a rich, deep, umami flavour. It's added to marinades, soups and sauces, and used to make pickles. The Ajinbou brand is HK$32 for 160 grams.
Morisho white plum paste comes in a tube, which makes it easy to use. The tart-salty paste, made in Wakayama, can be used as you would ordinary umeboshi (which translates as sour plums, although they're actually apricots) - and a little goes a long way when added to onigiri (rice balls) or used in a dip. The paste costs HK$50 for 130 grams.
There's no way uni hishio (salted sea urchin sauce) will take the place of fresh sea urchin, but it can be enjoyed as something entirely different. Hishio - pickled and salted meat or seafood - is a traditional Japanese method of food preservation. The Obama brand version, made from sea urchin, salt, sugar, onion, thickeners and paprika, comes from Fukui, and is good drizzled over rice or pasta. The sauce costs HK$118 for 140 grams.