Most likely these badges were issued to the participants of an unknown conference. Original ribbon is missing.
Size 51 x 17 mm.
Thickness 7 mm.
Stylized combined logos of two railways South Manchurian Railway /Manetsu/...
See also https://asiamedals.info/threads/chosen-manetsu-railways-visiting-group-badge.24385/
Reverse
満鮮旅行記念 - Chosen-Manetsu Travel Commemorative
昭和五年六月 - June 1930
1930 chosen-manetsurailways travel badge
1930年六月満鮮旅行記念章
chosen-manetsurailwaysbadge
korea under japanese rule
korea under japanese rule badge
昭和五年六月満鮮旅行記念章
満鮮旅行記念章