In the Japanese calendar, seasons traditionally followed the lunisolar calendar with the solstices and equinoxes at the middle of a season. The traditional Japanese seasons are:

• Spring: 4 February–5 May
• Summer: 6 May–7 August
• Autumn: 8 August–6 November
• Winter: 7 November–3 February

In categorising kigo, a saijiki or kiyose divides each season into early, middle, and late periods, as follows:^[2]

• Early spring: 4 February–5 March
• Mid-spring: 6 March–4 April
• Late spring: 5 April–5 May
• Early summer: 6 May–5 June
• Mid-summer: 6 June–6 July
• Late summer: 7 July–7 August
• Early autumn: 8 August–7 September
• Mid-autumn: 8 September–7 October
• Late autumn: 8 October–6 November
• Early winter: 7 November–6 December
• Mid-winter: 7 December–4 January
• Late winter: 5 January–3 February

English edit

• The Five Hundred Essential Japanese Season Words, selected by Kenkichi Yamamoto, on Renku Home
• William J. Higginson, ed. Haiku world: an international poetry almanac. Kodansha, 1996. ISBN 978-4-7700-2090-1
• The Japanese Haiku Topical Dictionary at the University of Virginia Japanese Text Initiative
• World Kigo Database, worldwide saijiki

French edit

• LE SAIJIKI: Ephéméride poétique à l'usage des poètes composant des haïku en langue française (in French) - Le Saijiki, the French version of the Saijiki by Seegan Mabesoone, has been available since 1998.

Japanese edit

• Masaoka Shiki, ed. Kiyose. 1930 (Japanese: 正岡子規 編『季寄せ』（三省堂、1930）)
• Kyoshi Takahama, ed. A New Saijiki, 1934 (Japanese: 高浜虚子 編『新歳時記』（三省堂、1934）)
• Teiko Inahata, ed. The New Hototogisu Saijiki, 1996 (Japanese: 稲畑汀子 編『ホトトギス 新歳時記』（三省堂、1996）＆ CD版（1998）)

• A Dictionary of Haiku, Classified by Season Words with Traditional and Modern Methods, by Jane Reichhold (AHA Books)

• Haiku in English
• List of kigo
• Renga, an older form of poetry employing kigo
• Renku, the poetic form from which haiku derived, also using kigo