Abstract
The Japan Meteorological Agency (JMA) is operating four geomagnetic observatories in Japan. Kakioka Magnetic Observatory (KMO), commissioned in 1913, is the oldest. The hourly records at KMO cover over almost 100 years. KMO is JMA's headquarters for geomagnetic and geoelectric observations. Almost all data are available at the KMO website free of charge for researchers. KMO and two other observatories have been certified as INTERMAGNET observatories, and quasi-real-time geomagnetic data from them are available at the INTERMAGNET website.