Is B flat called H in northern Europe?

Yes, in Germany, the Netherlands, and some other northern European countries, B flat is called H, while B natural is called B. This naming convention is based on the German musical alphabet, which uses the letters H and B instead of B flat and B natural. The German musical alphabet is as follows:

A, B, C, D, E, F, G, H, I, K, L, M, N, O, P, Q, R, S, T, U, V, W, X, Y, Z

In English-speaking countries, B flat is called B flat and B natural is called B. The English musical alphabet is as follows:

A, B, C, D, E, F, G, A, B, C, D, E, F, G, A, B, C, D, E, F, G, A, B, C