One of the most fun things about exploring far-outlying places in Japan is the conversations you fall into. We had several such conversations in Tsuruga, the Japan Sea port city closest to Osaka and Kyoto, which for that reason became the terminus of one of Japan's first railway lines. (The other two connected the port of Yokohama with Tokyo and the port of Otaru with Sapporo.)
On a visit to the Kehi Matsubara pine grove and beach, we stopped at a shady refreshment stand to get some cool drinks. Near the vending machine sat two elderly men, one grizzled and talkative, the other silent and dignified. The grizzled man seemed to have saved up many things he wanted to share with English-speakers, starting with his futile attempts to learn our language. His teachers had concentrated too much on grammar, he said, and the only English phrase he could reliably remember for all his trouble was "I forgot." He said Chinese speakers had much greater success learning English because of the similarities in word order between the two languages, and that Mongolian sumo wrestlers learned Japanese much more quickly than the European wrestlers for similar reasons.
He was originally from Kochi (formerly Tosa) in Shikoku, and when I asked about the famous Tosa fighting dogs, he launched into a long disquisition on their virtues (such as silently enduring pain like samurai) and superiority over Akita dogs, which might be larger but lacked the same degree of fighting temperament.
His dignified companion, who never got a word in edgewise, was a former officer in the Imperial Japanese Navy who was recruited by the Occupation authorities to clear mines from the harbor. The word (new to me) that Mr. Grizzly used for 'naval mine' was 魚雷 gyorai lit. 'fish-thunder', which more commonly refers to torpedoes, as in 魚雷艇 gyoraitei 'torpedo boat'. (Torpedoes are also called "fish" in anglophone sailor slang.) Aerial torpedoes are 空雷 kuurai 'air-thunder' and a torpedo attack is 雷撃 raigeki 'thunder-attack'.
The generic word for 'mine' is 機雷 kirai 'device-thunder'. Naval mines are 水雷 suirai 'water-thunder' and land mines are 地雷 jirai 'earth-thunder', as in 地雷原 jiraigen 'minefield'.
This encounter reminded me of a story my Uncle Murray told for the first time back in April, when I had the chance to attend a brief reunion of my father and his only two surviving brothers. Uncle Murray reached draft age right at the end of World War II and he was on his way to invade Japan in August 1945 when Japan surrendered and his ship put into Midway to await a change of orders. His unit was then rerouted to the Philippines, where they assembled Japanese POWs as they surrendered and then put them to work helping to dismantle and destroy military stockpiles near Manila. His POWs would load electrical equipment onto amphibious ducks, which he would then drive out to sea, where the POWs would drill holes in the batteries and dump them in the ocean, often getting very seasick in the process. Much of Manila had been destroyed during the war, and Uncle Murray said his unit's battery disposals must have destroyed a lot of life in the surrounding seas as well.