Possible Clues:

• Poem with a 5-7-5 syllable pattern
• Island nation reflected after chap discovered Japanese writing
• Reportedly excellent masterstroke to produce short verse form
• Basho work
• A poetry form/With seventeen syllables/And only three lines
• Oriental poem with sound of excited talk as lovebirds do
• Three-line form reported power grab at top level?
• What’s poetic greeting heard the country over?
• Stylised Japanese poem of 17 syllables
• Eastern verse