Is it okay to use つ counting for everything?

Instead of using the proper counter for each thing, is it okay to just use the つ counter?

Like in:

Are there situations when this is incorrect or not recommended?

• Off topic: it's much more natural to use 2匹 adverbially, e.g. 子猫を２匹. Sep 15, 2015 at 23:30
• And "to have (a pet)" is (ペットを)飼【か】っている. 持っている is wrong unless you mean holding two cats in one's arms. Sep 16, 2015 at 1:59

つ is a generic inanimate counter. It might be confusing sometimes, but you can get away with using it for lots of inanimate objects if you don't know a more appropriate counter.

Don't use つ for animals or people.

You should use 匹 for kittens in your example, not つ. The basic counter for people is 人{にん}.

In general, animate objects (animals and people) have special counters. No matter how long and thin a snake may be, you can't use the inanimate counter for long and slender objects (本) to refer to it. And you should never refer to people like they're inanimate objects.

If you don't already know them, you should try to learn some basic counters at some point. Planning on using つ all the time is no good. Some of the most common ones include 人・名・匹 (animates) and 本・枚・台 (inanimates), along with つ and 個.

• It is said that つ counting is only up to 10. This limit denotes the max for つ counting or just the hito-futa-mi numbers? 個 also has this limit? Sep 15, 2015 at 8:31
• @BrunoLopes It's because つ is no longer "productive", which means it doesn't combine with new things anymore. All the combinations of つ with numerals are pre-formed in the Japanese vocabulary, and there are only nine of them (plus とお, where つ is technically absent). 個 is still productive and can attach to larger numbers (from the other system, of course).
– user1478
Sep 15, 2015 at 8:47
• So "25 books" could be 本25（にじゅうご）個　? Sep 15, 2015 at 9:34
• For 本(book), use [冊]{さつ}... eg 彼女は本を[25冊]{にじゅうごさつ}持っています。 Sep 15, 2015 at 13:39
• @choco But in case 個 is used, as a general object counter, would the sentence be correct? Or it can't be used for books? Sep 15, 2015 at 18:09

It might work for most objects.

For some other concepts it won't be understandable at all, though, for instance don't use it for:

• Hours/days/months/etc
• People (as snailboat said)
• Number of occurences
• Distances