The 'サ' in this emoji is the first character of the word 'service' (サービス). It's common in Japan to abbreviate long words using just the first character, and this is one such example.

This emoji requires an understanding of Japanese culture, so users from other cultures often misunderstand it. For instance, its blue background might lead people to think it means something positive or 'free,' but it actually signifies an 'extra charge.' The Japanese emoji for 'free' is 🈚️ (mu).