haha ha kata ni sippu wo hatte ita node, kyou ha omoi nimotu wo motasenakatta.

は marks 母 as the topic: As for my mother...

It does not just mean subject in a mechanical way. Here it sets up the person the sentence is about, and the rest of the sentence gives information about her situation.

If the sentence used が instead, it would sound more like it was identifying or focusing on mother specifically. With は, the sentence feels more like normal narration.

With 貼る, the thing being attached takes を, and the place or target surface takes に.

So:

• 湿布を貼る = attach/apply the patch
• 肩に貼る = attach it to the shoulder

Put together:

• 肩に湿布を貼る = apply a patch to the shoulder

This pattern is very common with verbs of attaching or placing something somewhere.

湿布 is a medicated patch, compress, or poultice used for pain relief, especially for stiff shoulders, back pain, muscle pain, and similar problems.

In everyday Japanese, it often refers to those adhesive pain-relief patches people stick on the body. So in this sentence, it is not just any sticker; it is a medical or therapeutic patch.

This is a very common point of confusion.

With 貼る, the 〜ている form often describes the resulting state, not just an action in progress. So:

• 貼った = put it on
• 貼っている = has it on / it is attached
• 貼っていた = had it on / it was attached

In this sentence, 肩に湿布を貼っていた does not necessarily mean she was in the middle of sticking it on. More naturally, it means she had a patch on her shoulder.

So 〜ていた here describes the condition she was in at that time.

Both ので and から can give a reason, but ので is usually a little softer, more explanatory, and less blunt.

• ので = because, since
• から = because, but often more direct or assertive

In this sentence, ので sounds natural because the speaker is calmly explaining the reason for what they did.

So the nuance is something like:

• Because she had a patch on her shoulder, ...
• not a strong argumentative because but an explanatory one

今日は makes today the topic or contrastive frame.

It can imply something like:

• as for today
• at least today
• today, in particular

So the sentence can suggest a contrast such as:

• maybe on other days she might carry things,
• but today the speaker did not let her.

This use of は is very common with time expressions when the speaker wants to frame or contrast the situation.

持たせなかった is the negative past causative form of 持つ.

Breakdown:

• 持つ = hold / carry
• 持たせる = make someone carry / let someone carry
• 持たせない = not make/let someone carry
• 持たせなかった = did not make/let someone carry

So here it means the speaker did not have her carry the heavy luggage, or did not let her carry it.

A natural way to understand it is that the speaker intentionally prevented that from happening because of her shoulder.

Japanese causative forms often cover both ideas:

• make someone do
• let/allow someone do

Which one is more natural depends on context.

In this sentence, because the speaker is protecting the mother, 持たせなかった is best understood as something like:

• I didn’t let her carry it
• I didn’t have her carry it

It is less about forcing and more about not allowing or not assigning that action to her.

Japanese often leaves this unstated if it is obvious from context.

The hidden subject of 持たせなかった is most naturally the speaker, such as I.

The person who would have carried the luggage is the mother, already introduced as the topic.

So the full idea is roughly:

• I didn’t let my mother carry the heavy luggage today.

If everything were spelled out more explicitly, it could look like:

• 私は母に重い荷物を持たせなかった。

But Japanese often omits things that are already understood.

Because once 母 has been established as the topic, repeating it would often be unnecessary.

Japanese strongly prefers omission when the meaning is clear. So instead of saying the equivalent of:

• Mother had a patch on her shoulder, so today I didn’t let mother carry heavy luggage

it simply leaves mother understood in the second clause.

This kind of omission is extremely normal and natural in Japanese.

Japanese often does not use possessives like my when the relationship is obvious from context.

So 母 by itself usually means my mother when spoken from the speaker’s point of view.

Also, 母 is the standard word used when referring to your own mother in a neutral/plain way to other people or in narration. By contrast, お母さん is often used when addressing your mother directly or when speaking from a more inside-family perspective.

荷物 refers to baggage, luggage, a load, or things someone is carrying.

It is more specific than a general word like 物. It suggests items being transported or carried.

So with 重い荷物, the image is something like:

• heavy baggage
• heavy bags
• a heavy load

That is why carry heavy luggage/bags sounds natural in English here.

Japanese nouns usually do not mark singular vs. plural unless the speaker needs to make that clear.

So 重い荷物 could mean:

• one heavy bag
• several heavy bags
• heavy luggage in general

The sentence does not specify the number. English often has to choose singular or plural, but Japanese does not.

持つ has a wide range of meanings depending on context, including:

• hold
• carry
• have
• possess

When the object is 荷物, the natural meaning is usually carry.

So:

• 荷物を持つ = carry luggage / carry bags

Even though the basic verb is the same one that can mean hold, the object tells you which English word fits best.

Literally it is shoulder, and that is the best reading here.

Japanese body-part words often do not specify left/right unless needed, so 肩に湿布を貼っていた simply means she had a patch on her shoulder. If left or right mattered, the sentence could say 右肩 or 左肩.

So the sentence is not trying to be anatomically precise; it is just giving the relevant physical reason.

Grammatically, 貼っていた can sometimes look like a past progressive, but in this sentence the natural interpretation is the resulting state:

• she had a patch on her shoulder

That is because with verbs like 貼る, 〜ている often describes the state after attachment. Also, that reading fits the logic of the sentence much better: her shoulder condition is the reason the speaker did not let her carry heavy luggage.

So while learners may first parse it as an ongoing action, the more natural understanding here is a state, not a process.