The sagittal axis¹ is an anatomical axis which extends forwards from the body. Points further along one’s axis are further ahead of them; the rear of the axis trails behind them.

In English, I think of the future as being ahead of me and the past behind. I can say that I am “looking forward” to something, or that “the worst is behind me”. Cher longs to “turn back time”. An exhibition might be a “retrospective” – the Latin adverb “retro” lends itself to hundreds of English words. In short, “before” and “after” are synonyms for “behind” and “ahead” in English. The flow of time is ➡️.

Chinese has a set of up/down particles: 上 shàng "up; above" / 下 xià "down; below". If events are an ordered list on a page, then 上次 shàngcì "last time" is upwards and 下次 xiàcì "next time" is downwards. This feels intuitive to me.

But Chinese has another set of particles: 前 qián "front; ahead" / 后/後 hòu "back; behind". This made a lot less sense to me when I first learned it.

Compared to the way I am used to thinking of time’s arrow (which extends outwards from my eyes and radiates ahead of me into the future), this is backwards. Consider 学前班 xué qián bān "preschool" which occurs 前 qián "before" school, an 派对之后 pài duì zhī hòu "afterparty" which occurs 后 hòu "after" a party, or the phrases 前天 qiántiān "day before yesterday" and 后天 hòutiān "day after tomorrow". Time’s arrow appears to flow backwards through the speaker.

But this also unlocks a lovely analogy: a speaker must walk blindly backwards towards the future. They can see the past, but the future lies forever out of sight.

In Chinese, I often get these two/three characters confused:

1. 殳 shū "halberd", which decomposes as 殳 ==> ⿱(几, 又).

   This is the (now rarely used) term for an ancient weapon. Often seen as the phonetic component in more common characters, such as 投 tóu "throw; fling".

2. The right half of 船 chuán "boat", which decomposes as ? ==> ⿱(几, 口).

   This isn’t a character but an alternative way of writing 㕣 yǎn "marsh", which decomposes as 㕣 ==> ⿱(八, 口).

3. 召 zhào "call; decree", which decomposes as 召 ==> ⿱(刀, 口).

   Common by itself in terms like 召开 zhàokāi "hold a meeting; convene", and as the phonetic component in 照 zhào "shine; illuminate", etc.

   This is easier for me to remember since “decreeing” something is like using your 口 kǒu "mouth" as a 刀 dāo "knife".

I have heard the term “confusable” used to describe different Unicode characters such as these. In Chinese, I often get these two characters confused:

1. 司 sī "control; manage". (Fun fact: Shuowen Jiezi¹ claims that this is 后 hòu "queen; emperor", flipped.) I usually see this character in 公司 gōngsī "company" or 司机 sījī "driver; chauffeur".

2. 同 tóng "same; together". I often encounter this as a “co-” -like prefix, such as 同事 tóngshì "coworker", or 同学 tóngxué "classmate".

One reason that I get them confused is that they both have the inner structure 𠮛 zhǐ², which appears to be a variant form of 旨 zhǐ rare enough to only appear within 司 sī, 同 tóng, and atop 畐 fú and its derivations ( 福 fú, etc).

Idiom

Tangyuan 汤圆 tāngyúan "soup balls" are a traditional Chinese dessert made of glutinous rice shaped into balls that are served in a hot broth or syrup.

This rhymes with 团圆 túanyúan "to reunite; to have a reunion". Because it can mean reunion in the sense of a family reunion, 汤圆 are often eaten during holidays.

Etymology

The term 汤圆 tāngyúan comprises two characters:

1. 汤/湯 tāng "soup"¹. decomposes as 湯 ==> ⿰(氵, 昜)

   role	character
   semantic	氵 shuǐ "water"; an abbreviated 水 shuǐ. This is common enough to have a nickname: 三点水 sandianshui "three droplets of water".
   phonetic	昜 yáng an unusual form derived from either (1.) 易 yì "change;exchange" or (2.) 陽 yáng (more commonly 阳, a.k.a. the yang of yin/yang)

2. 圆/圓 yúan "circle; round". decomposes as 圓 ==> ⿴(囗, 員)

   role	character
   semantic	囗 wéi "enclose; surround". (Not to be confused with 口 kǒu "mouth".)