訓 ふた(つ) ・ 音 ニ
Sino-Vietnamese: nhị
Two horizontal strokes stacked, the lower one slightly longer. For one, two and three the stroke count is the number itself, so just count the lines.
Stroke data: KanjiVG (CC BY-SA 3.0) — kanjivg.tagaini.net
猫が二匹います。 (ねこがにひきいます)
There are two cats.