本 is a counter word that is primarily used to count long, and mostly cylindrical, objects.
| (I) bought two ballpoint pens. | ボールペン を 二本 買いました。boorupen o nihon kaimashita. |
| There are four rivers. | 川 が 四本 あります。kawa ga yonhon arimasu. |
The pronunciation of 本 changes based on the number it's counting due to a linguistic phenomenon called rendaku or sequential voicing, in exactly the same way as the counter 分 for minutes, because both start with an h sound.
| one long, cylindrical object | 一本ippon |
| two long, cylindrical objects | 二本nihon |
| three long, cylindrical objects | 三本sanbon |
| four long, cylindrical objects | 四本yonhon |
| five long, cylindrical objects | 五本gohon |
| six long, cylindrical objects | 六本roppon |
| seven long, cylindrical objects | 七本nanahon |
| eight long, cylindrical objects | 八本happon |
| nine long, cylindrical objects | 九本kyuuhon |
| ten long, cylindrical objects | 十本juppon |
Now we're finally ready to order some beer!
| Please give me three bottles of beer. | ビール を 三本 ください。biiru o sanbon kudasai. |
| (I) bought eight candles. | 八本 の キャンドル を 買いました。happon no kyandoru o kaimashita. |
| He ate six bananas! | 彼 は 六本 の バナナ を 食べた よ。kare wa roppon no banana o tabeta yo. |
| (I) plan to read ten books. | 本 を 十本 読む つもり です。hon o juppon yomu tsumori desu. |
