I had lovely tempura lunch ! Good Tempura is really difficult to cook perfectly. Flour thickness, temperature of the oil etc etc…
When I talked with the tempura chef, he said “tempura is not a deep-fried dish(it is a deep fried as cooking technique itself) but it’s a steamed dish actually” . I didn’t understand why he said so straight away but according to him, the ingredients are steamed in the shell of tempura flour… that’s why the ingredients are cooked juicy and taste good. That’s a very unique way to describe good tempura but really true… I think.
If there is a counter in the tempura restaurant while your visit in Japan, I strongly recommend for you to find a seat at the counter if it’s available cos you can enjoy fresh and crispy tempura from the chef just in front of you! (some tempura restaurant may allow you to take a seat at the counter when you order a la carte. Ask the restaurant when you visit or book a table!) 
Ellie's Food Diary 
I always thought it was deep fried! Hopefully we get to visit Japan one day. It’s on my list. 😀
Actually the way of cooking is deep fried (your understanding is correct too) but he tries to explain to me that its deep fried dish but the ingredients are steamed at the same time 😉 it’s a kind of complex story but as he says good tempura is not so oily and the outside flour is really thin.
Tempura needs professional skill and the chef said it takes 10 yrs to become a very good tempura chef. But fast food version of tempura is a little oily and mostly flour is so thick especially prawn tempura. Sometimes flour part is more bigger than inside prawn and doesn’t look very healthy for me. So I try not have those fried cos ingredients are usually overbooked and not juicy too. Yes! Hope you will visit Japan someday and enjoy authentic tempura by professional skill ! 🍤
Thank you for explaining this to me. Now I understand. Wow, 10 years is a long time. It really needs a lot of practice. I can imagine that.
Yeah, hopefully I can visit soon. 😃