This paper aims to discuss characteristics and challenges of Learning Group Formation (LGF))(Gakushu Shudan Zukuri). The fact that there has been no good summary of LGF theory and research practice in English, this paper describes how the theoretical framework of the LGF has been founded, specifically with corresponding with practical problematic situations of teaching and schools. In the end, we will show the characteristics and challenges of lesson study and lesson analysis of LGF citing a specific example of lesson analysis to indicate how they have been approached from four perspectives.