One day before the Dec. 7, 1941, attack, Japan had a pretty good idea what ships were, and weren’t, in Pearl Harbor — because an Imperial Japanese Navy spy in the Japanese Consulate in Honolulu was dutifully reporting the fleet’s status.

Takeo Yoshikawa’s final message was relayed to Vice Adm. Chuichi Nagumo, whose 31-ship attack fleet, including six aircraft carriers, was racing toward Oahu on a moonlit night.

“Dec. 6 (local time). Vessels moored in harbor: nine battleships, three Class-B cruisers, three seaplane tenders, 17 destroyers. Entering harbor are four Class-B cruisers, three destroyers. All aircraft carriers and heavy cruisers have departed harbor,” Yoshikawa reported.

The tally was not completely accurate, but Yoshikawa had been filing regular reports on the American fleet.

In 1941 the Honolulu consulate was known to be a hotbed of spy activity and a key link in the chain of Japan’s naval intelligence, Gordon W. Prange, Donald M. Goldstein and Katherine V. Dillon wrote in “At Dawn We Slept.”

Yoshikawa, 27, arrived in Honolulu in March 1941 under the pseudonym Tadashi Morimura, ostensibly as the new vice consul in town. His real job was intelligence collection.

“As a basis for my efforts, I knew that Japan would attack the United States,” Yoshikawa said in a first-person account of his espionage in the December 1960 edition of the U.S. Naval Institute magazine Proceedings.

He found that his diplomatic status, together with the large Japanese population in the islands, “permitted me to move about with remarkable freedom.” He often rented aircraft at John Rodgers airport for surveillance of military airfields. He also walked nearly every day through Pearl City Peninsula to survey Ford Island and Battleship Row.

But perhaps Yoshikawa’s most successful vantage point was from the Shunchoro Tea House on the slopes of Alewa Heights, later the Natsunoya Tea House. “On many nights, after I had made my preliminary observations, I would wind up at the Shunchoro in a little Japanese-style room, grateful to be sitting on the rice-straw tatami mats again and talking once more with a geisha,” he said.

Yoshikawa attempted to recruit others to his cause, but “the Japanese population of Hawaii we found essentially loyal to the United States.”

The military and FBI kept a watchful eye on the Japanese Consulate. FBI Honolulu bureau chief Robert Shivers personally questioned Morimura/Yoshikawa and Consul-General Nagao Kita several times, Marc Wortman said in his book “1941: Fighting the Shadow War.”

Yoshikawa was under surveillance from the moment he arrived in Honolulu and a tap was placed on his consulate phone.

Unknown to most was that U.S. intelligence was reading the consulate’s coded communications.

Ten days before the attack, Kita and Yoshikawa received indication that “X-Day” was not far off. An Imperial Japanese Navy officer arrived on a liner disguised as a ship steward and delivered 97 detailed questions. Among them was, “On what day of the week would the most ships be in Pearl Harbor on normal occasions?” “Sunday,” was the answer.

“Are the ships fully provided with supplies and ready for sea?” “They are not ready for combat,” Yoshikawa responded.

He was at breakfast when the first bomb fell on Pearl Harbor. At about 8:30 a.m. the police arrived at the consulate, and the FBI began searching for evidence of espionage, Yoshikawa said.

“Except for a half-finished sketch of Pearl Harbor, forgotten in my wastebasket, nothing incriminating was found,” he said. That one item was disregarded.

Kita was interviewed by a Honolulu Star-Bulletin reporter that morning and said he thought the bombing was “maneuvers” by U.S. forces. He claimed to have been “lazy this morning and didn’t get up until late.”

After about 10 days’ confinement in the consulate, the staff was taken by Coast Guard vessel to San Diego, and returned to Japan via the Swedish ship Gripsholm in August 1942, Yoshikawa said.