Iwakawa was born in Inaniwa Town (now part of Yuzawa City), Akita Prefecture, Japan, on 25 February 1909. He graduated from junior high school in Inaniwa Town while working as a live-in apprentice with a local landowner. Influenced by his father, who was an administrative scrivener, in 1933 (Showa 8), at the age of 24, he became certified as a judicial scrivener and became independent.

While working as a judicial scrivener, he also produced Inaniwa udon, one of Japan’s three major types of udon. During World War II, he served in the Navy in Yokosuka City, Kanagawa Prefecture, and returned to Akita when the war ended. At some point, he got married and had two sons and two daughters. Until he was 95 years old, he worked as a judicial scrivener in Yuzawa City, mainly engaged in real estate sales and sales registration, and was trusted as the only judicial scrivener in the area.

Iwakawa continued to remove snow from the roof of his house until he was around 90 years old and began composing tanka after his wife Hana passed away in 2006. In 2009, Mayor Yuzawa visited his home to celebrate his 100th birthday. During that occasion, he attributed his longevity to his practice of rinsing his nose twice daily for decades to prevent colds. At the age of 105, he was able to maintain a posture that kept his back straight, his legs strong, and he did not use a cane. At the time, he was still doing his own cooking and laundry. In February 2019, he celebrated his 110th birthday, and the mayor once again congratulated him and presented him with a commemorative gift. He had three great-grandchildren at the time. When he turned 110 years old, he said, “I never expected to live this long.”

In early March 2019, he became unwell and was hospitalized. On March 21st, he passed away of natural causes at a hospital in Yuzawa City at the age of 110 years, 24 days. His second son, Yoshifumi, commented, “He was a person who took charge of his own health and had an independent spirit.”