What does this capacitor symbol mean?

As mentioned… its a Japanese notation of a standard electrolytic capacitor. The Schematic symbol used on the board does not denote a special kind of capacitor. While not used as much today, it is very prevalent in older schematic diagrams that were designed by Japanese engineers… it does NOT mean you need to use a special Japanese manufactured capacitor. Its just the Symbol that they used for polarised electrolytic capacitors.