The National Institute for Japanese Language and Linguistics, Japan (NINJAL, Japan), has developed several types of corpora. For each corpus NINJAL provided an online search environment, 'Chunagon', which is a morphological-information-annotation-based concordance system made publicly available in 2011. NINJAL has now provided a skewer-search system 'Kotonoha' based on the 'Chunagon' systems. This system enables querying of multiple corpora by certain categories, such as register type and period.