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In this lesson, we'll learn about the native set of numbers that coexist with their Sino-Japanese counterparts. In doing so, we'll begin our journey of learning how to count things by introducing the most important counter in Japanese - ～つ.  

Numbers existed in Japanese prior to Sino-Japanese words being incorporated into the language. In modern speech, only the native words for 1 through 10 are practically used given the extreme influence the Sino-Japanese numerals have had.

When counting in general, the counter ～つ attaches itself to the base number with exception to とお (10). 

※The pronunciations that exclude っ are the traditional ones, but they have largely fallen out of use in favor of those that include it. 

※いく stands for "how many?" 

When counting, speakers may choose to use these phrases instead of Sino-Japanese numbers. This gives ひとつ, ふたつ, みっつ, etc. Interestingly, though, there is an abbreviated form for counting numbers that reduces to monosyllabic yet moraically elongated counterparts. 

When reciting these, they are often just left as one mora with 5 and 7 often being rendered irregularly as いつ and なな respectively, resulting in: ひ・ふ・み・よ・い（つ）・む・な（な）・や・こ・と. 

First, it's important to understand what is meant by counting things. As straightforward as "one bird, "two birds, "three birds," etc. might seem, in Japanese, you need to combine numbers with the counter for said object. Thus, you combine "1, 2, 3" with the counter for bird in this case. The counter aids the number in defining what is being counted. 

Although the counter for "bird" is unfortunately not the native word for bird, native counters are often standalone nouns that bear the same meaning, which is very familiar to how such expressions are typically made in English.

1. ひと切れのパン　（切れ ＝ piece/slice)
A piece/slice of bread

2. ふた月 　(月 = month)
Two months 

3. ひと房のブドウ　 (房 = bundle)
A bundle of grapes 

Though this correlation is not absolute, encountering new native counters is easier knowing this beforehand. Quantity words often function as counters, and when that word has to be a native one, expect it to at least go with the first few numbers of the native sequence before switching over to Sino-Japanese numbers*.

※Knowing how Sino-Japanese numbers still get interjected with native counters will be a future topic of discussion.

Given that the majority of counters are also Sino-Japanese, it might seem counterproductive to start learning them from the native vocabulary route, but the reason for this is due to just how important the counter ～つ really is. 

It goes without saying that ～つ can theoretically count anything and everything. It is the most used counter by far, which would make sense considering it was the first of its kind. The reason why it gives off this impression is the sheer scope in what it does generally count as well as its ability to replace the proper counter of an entity out of convenience or due to lack of knowing. 

How ～つ is generally used can be simplified to the following seven points. Note that in order to demonstrate how it competes with other (sometimes more proper) counters, those said counters are shown in parentheses as reference material and need not be studied until they are formally introduced. 

1. Counting Three-Dimensional Items

Most physical items have a proper counter that is generally used to count it, but there is still a plethora of physical objects that are assigned to ～つ. When ～つ does replace another counter, it gives off a very colloquial tone. 

4. 2つ下さい。
Please give me two (of them).

5. ブースは4つあります。
There are four booths.

6. オフィスにテーブルが5つあります。
There are five tables in the office.

7. 日本には、温泉はいくつ（→ 何か所）ありますか。

How many hot springs are there in Japan?

8. ベッドは５つ （→５床 ・５台）あります。
There are five beds.

9. 飴をひとつ（→ 1個）食べます。
I’ll eat one piece of candy.

2. Counting Things w/ Indeterminate Shapes

Not everything has a defined shape, and those entities are even more likely to be counted with ～つ. 

10. タオルに黄色い染みが2つあります。

There are two yellow stains on the towel.

11. 洗面台の下に大きな水溜まりがひとつあります。
There is a large puddle beneath the washstand.

12. 影が3つありました。
There were three shadows.

3. Counting Abstract Things

Given how ～つ can both be used to count things regardless of shape, it is only logical that it may count abstract things which have no physical shape. 

13. 理由は6つあります。
There are six reasons.

14. ミッションは7つあります。
There are seven missions.

15. 条件は1つあります。
There is one condition.

16. 交わした十（じゅう）の約束はひとつも守らなかった。
You didn’t even protect one of the ten promises we made.

Grammar Note: Ex. 16 shows how once you count past 9 with an entity counted with ～つ, the pattern is halted and switches over to using Sino-Japanese numbers without a counter at all or Sino-Japanese numbers + the counter ～個, which is the Sino-Japanese equivalent of ～つ that we'll learn about in the next lesson. 

4. Replacing the Proper Counter

Given how ～つ is both generic and versatile, the reasons for why ～つ migh replace the proper counter of an entity are also numerous. The speaker may not know the counter, the counter in question could be too obscure when spoken, or using ～つ is just simpler, case in point.  

17. 金曜日に授業はいくつ（→ 何クラス）ありますか。

How many classes do you have on Friday?

18. 家の2つ前の駅で（→ 2駅前で）友達と待ち合わせました。
I met with a friend at the station two stations before my place.

Grammar Note: Something that will be emphasized more clearly in the following lesson is how counters may behave as adverbs, but how adverbial a counter is can differ on a case to case basis, which explains why more than just a counter swap occurs in Ex. 18. The option in parentheses treats "two stations" as a fully adverbial phrases, whereas 2つ前の駅 utilizes both a counter and the literal noun it is counting juxtaposed next to it. 

5. Replacing Proper Counter in Orders

A sub-usage of Usage 4, it is very common for ～つ to replace the proper counter of something when ordering. One major reason for this is that when ordering various items, the proper count for each may all be different, and to simplify your ordering, assigning ～つ to everything would be the most efficient option. 

19. チーズバーガー２つとLサイズのポテト３つ下さい。

Two cheese burgers and three large-sized orders of french fries, please.

20. ハムサンドイッチとコーヒーをひとつ下さい。
One ham sandwich and coffee, please.

21. アイスコーヒーを1つ（→ 1杯）下さい。
One iced coffee please.

22. アマゾンでゲーミングチェアを2つ注文した。
I ordered two gaming chairs on Amazon. 

To express someone being X years older/younger than someone, all you do is follow the pattern ＃つ上（うえ）・下（した） accordingly. 

23. うちの子は3つです。
My child is three.

24. 兄は8つ上です。
My older brother is eight years older.

25. 妹は五つ下です。
My younger sister is five years younger.

26. 僕は今年で8つになるんだ！
I'll be 8 this year. 

Grammar Note: 十(とお） can be used to mean “ten-years-old,” but after 10 with, of course, exception to 20, the Sino-Japanese method of counting age is used.

27. 視聴者（たち）の心がひとつになったでしょう。

The hearts of the viewers surely became one. 

28. こうして幼い頃から一つの屋根の下で育ちました。
This is the way (we) grew up under the same roof since (we) were little.

29. ひとつ聞いてもいいですか。
Can I ask you something?