Final answer:
The hichiriki is the primary woodwind instrument in the gagaku orchestra, measuring about 18 cm in length, prominently featured in the gagaku orchestra, where it leads the melody.
Step-by-step explanation:
The hichiriki is a significant woodwind instrument in the gagaku orchestra, known for its distinctive sound. A) In response to the student's question, the primary woodwind instrument in the gagaku orchestra is indeed the hichiriki itself. B) A typical hichiriki measures about 18 centimeters (7 inches) in length. C) The gagaku orchestra, which is the traditional imperial court music ensemble of Japan, prominently features the hichiriki. D) Within a gagaku performance, the primary role of the hichiriki is to lead the melody, often accompanied by the shamisen, which adds musical color to enhance the scene.
To put it in context with other instruments, during tuning in an orchestra, while some woodwind instruments play high frequency notes, stringed instruments like the shamisen will play notes of varying frequencies that contribute to the overall harmony and mood.
Generally, wind instruments use finger holes, valves, and other mechanisms to change the air column's length, altering the frequency of the notes played. The hichiriki follows a similar principle to produce its unique sound that stands out in the gagaku ensemble.