Bottom dead center - Kasten

Japanese: 下死点 - かしてん

...In addition, magnetic ignition devices that use permanent magnet AC generators instead of storage batteries are also used in motorcycles and other vehicles.
[4-cycle system and 2-cycle system]
The top and bottom positions of a piston as it reciprocates are called top dead center and bottom dead center, respectively, the distance between them and the movement of the piston are called a stroke, and the series of intake, compression, expansion, and exhaust processes is called a cycle. An engine that performs one cycle in four strokes is called a four-stroke engine, while an engine that does not have independent intake and exhaust strokes and performs gas exchange near bottom dead center during the compression and expansion strokes is called a two-stroke engine.

From [Dead Point]

…the points at which the piston reaches its highest and lowest position when it reciprocates within the cylinder of a reciprocating engine. The highest point is called top dead center, and the lowest point is called bottom dead center. At dead center, the piston and the connecting rod are in a straight line, so even if a large force is applied to the piston, no moment is generated to rotate the crank. …

*Some of the terminology that refers to "bottom dead center" is listed below.

Source | Heibonsha World Encyclopedia 2nd Edition | Information

Japanese:

…このほか蓄電池の代りに永久磁石式交流発電機を用いたマグネット点火装置もオートバイなどに利用されている。
［4サイクル方式と2サイクル方式］
　ピストンが往復する際の最上位置，最下位置をそれぞれ上死点，下死点，その距離およびピストンの運動を行程と呼び，また一連の吸気･圧縮･膨張･排気過程をサイクルという。一つのサイクルを四つの行程により行うエンジンを4サイクルエンジン，また独立した吸･排気行程をもたず，ガス交換を圧縮･膨張行程中の下死点近くで行ってしまうものを2サイクルエンジンと呼ぶ。…