As the seasons change, the days are warm, but the mornings and evenings are still cold.
I want to wear spring clothes as soon as possible, but I hate being cold. In such a case, heat tech underwear and "stall vest" are convenient!
It's still chilly to have just one cut-and-sew dress like this.
Wearing Uniqlo's short-sleeved HEATTECH inside will keep you warm.
Also, there is a trick to making the heat tech invisible when wearing clothes that are slightly open in the back like this. By reversing the front and back of the HEATTECH, you won't be able to see your underwear from behind.
Furthermore, by putting a "stall vest" over the top like a vest, the warmth will be quite different. It does not interfere with the dress, and it can be used as an accent to complete a highly fashionable outfit. 
When it gets warm during the day, take it off and fold it small and put it in your bag.
I was looking for such a convenient item! If you think, how about one piece?