Cake flour
Fine, low-protein wheat flour, the Japanese hakurikiko, for tender cakes and light tempura batter.
In German-speaking countries, Type 405 is the ordinary household flour and is sold in every supermarket. In the UK and some other English-speaking countries, flour labelled as cake flour is less common; it can be found in well-stocked supermarkets, in Asian grocers as Japanese soft wheat flour, or by mail order.
Substitute:
Ordinary plain or all-purpose flour with about 15 g of every 100 g replaced by cornflour, sifted well together; this lowers the protein content, so sponge cakes and tempura batter turn out nearly as tender.