Associate Professor Shinobu Araki of the Institute of Art and Science of Yamagata University and her students have challenged the mystery of history through the first full-scale archaeological research in huge, nationally-famous hallowed grounds such as Yamadera Risshaku-ji Temple (Yamagata City), Jion-ji Temple (Sagae City) and Dewa Sanzan ranges (Tsuruoka City). The history of temples and shrines tend to be unknown because the literature and documents were lost due to the turmoil of wartime, anti-Buddhist movement and fire. The steles, on the other hand, are unburnable and still in existence to tell us a lot about the past. By checking and recording the design, stone type and carved characters of each gravestone, memorial stone tower and stone lantern, students try to analyse the background comprehensively. They ultimately try to know how the hallowed grounds have been changed along with time and decode who built the steles when for what purpose. Since 2013, the comparative research projects have been conducted outside of Yamagata Prefecture, such as in Matsushima in Miyagi Prefecture and Hiraizumi in Iwate Prefecture. The spirituality and religiosity in Yamagata will be researched for the future.