Linked from
The 11 pages that link to Koan, each with the reason it gives.
Buddha-natureRelated: Kōan practice can unsettle habitual views that obscure Buddha-nature.
Hakuin EkakuRelated: Hakuin made systematic koan training central to Rinzai discipline.
SōtōCompared with: Kōan-centered training is more strongly associated with Rinzai than with Sōtō.
Sokei-anRelated: Koan practice was central to the Rinzai tradition he transmitted.