In this paper, we investigated the effects of hint-presentation and repetitive production on generation of novel ideas through three experiments. We asked subjects to generate nonwords using Hiragana characters as many as possible for 5 minutes. The generated nonwords dominantly contained characters of Seion category, but its frequency decreased when subjects were presented with characters of other categories (Dakuon category in Experiment 1 and Choon and Sokuon categories in Experiment 2) before the task. Experiment 3 revealed that, in order to decrease the Seion, it was more effective to show a variety of characters as exemplars than showing all the available characters as a chart. The Seion tended to decrease also when subjects repeatedly produced the nonwords. Further analyses showed that repetitive use of same characters linearly increased while the variety of used characters reached ceiling as subjects repeatedly generated nonwords. It was also revealed that the transition of characters within produced nonwords was strongly influenced by normative order of Hiragana characters. We discussed these findings in terms of strategy to enhance creativity.