OKAYU, rice porridge, is very common to serve for sick people in Japan,
especially when they have problem with digestive system.
All ingredients is only rice, water and salt.
UMEBOSHI, dried and pickled salty plum, is often served with OKAYU. It tastes really sour.
UMEBOSHI is "Pavlov's dogs" for Japanese.
When many Japanese just imagine UMEBOSHI in their head,
the memory of sour flavor makes them salivate!