昭和41年 (Showa 41) is 1966 in the Western calendar. Check the age and zodiac below.
Yes. Showa 41 (昭和41年 in Japanese) corresponds to 1966 in the Western calendar.
1966 is the Year of the Horse (午（うま） in Japanese) in the 12-year zodiac cycle. In the older 60-year sexagenary cycle (kanshi) it is 丙午.
It depends on whether they have had their birthday yet this year. The box near the top of this page calculates both possible ages automatically from today's date — the lower number is their age before their birthday, the higher number is their age after.
Showa 41 is written 昭和41年 in Japanese. It is also commonly abbreviated S41 — for example on driver's licenses and other government forms.
