Difference between 氣 and 気

[ningen]

What is the difference between 氣 and 気?
I noticed that both are being used as spirit/soul
I also noticed that Aikido is being written as 合気道 but also as 合氣道.

 

[undrentide]

気 is simplied 氣.
The latter is one of the 旧漢字 (kyuu kanji = old kanji) and they are not used officially any more.
Here's the list of 新漢字 (shin kanji = new kanji) and 旧漢字.
旧 at the top, 新 is right below 旧.
気 and 氣 are shown in the 3rd paragraph.

パソコンで表示できる旧漢字一覧