Do the Japanese understand written Chinese?

If you have a good Kanji "vocabulary" (for lack of a better word) are you able to understand a text written in Chinese, or are there too many characters or combinations of characters that have a different meaning or simply do not exist in Chinese?

If you ask me (I am Japanese), my answer would be no.

While some kanji do overlap in their current meanings between Chinese and Japanese, there are many characters that have come to mean different things, and particularly the "simplified" Chinese writing is difficult.

No... just a some very simple words such as 日本人 (Japanese) is ok though.
Meaning of words are often different even if kanji is the same.
大家 is "landlord" in Japanese while it is "everybody" in Chinese.
汽車 is "steam train" in Japanese while it is "vehicle" in Chinese.

And, most Japanese cannot read/write simplified kanji (except its leaners) athough Japanese can probably understand some of traditional kanji.
发・・・kanji in simplofied Chinese
發・・・kanji in traditional Chinese
発・・・kanji in Japanese

I understand what others say that some characters have different meaning.
But when I (Japanese) and my husband (Australian) travelled to Beijing, our driver didn't speak much English. So we communicated using Kanji. It wasn't complicated conversation, but writing down Chinese characters certainly helped us understand each other!

I think most people can guess, especially when it's something simple.

For example, when I first visited China, I didn't know how to ask for the restroom, but later I saw a sign that said 厠 (or a simplified form of the letter) and realized that that's what I should've written for them. That is clearly a letter that represents the toilet to the Japanese. We even still see the same sign in Japan in Japanese.

On that trip, I successfully communicate a lot of times by writing random letters. For example, I would write 頭 (head) 痛 (ache) 薬 (medicine) one by one, and the drug store guy gave me the proper medicine. We were also able to make sure how you take it, by writing letters like 食後 (after meals) as well as numbers.

Names are easier read than said. All location names (such as city names and station names) are written in the same way in Japan, although pronounced very differently. So it's very easy to tour the cities by yourself.

Goofs: When we were in Hong Kong we found a sign that says 粥 (porridge) and assumed we can have supper. It turned out that it was a sweets shop and everything on the menu was extremely sweet pudding-like things. Another time was that, after we made a reservation (by writing some letters again) a clerk wrote about six letters and we couldn't figure out that it said "Thank you. We expect to see you all at six o'clock."

I know that Italian and Spanish is very similar, and also Spanish and Portuguese is written very similarly even though the pronunciation is very different, but Japanese and Chinese is much different from each other. I think the biggest obstacle is that the grammar is very different. We do learn ancient Chinese at school (because that's what intelligent ancient Japanese males used to write), but hey, no one remembers what you learn at school.

Also there is a book with phrases and important words for travellers, names konnichiwa nihongo. They have next to the English translation also Chinese translation.

Btw, do people in Japan read Lao Tsu, if so is it called the dao te king or do they use the japanese onyomi reading?

We learn about 老子 (Roushi) at school. Most people including myself won't understand if you say "Lao Tsu" or "dao te king". Same thing with 孔子 (Koushi). I just can't link "Confucius" with him!

I found a list of ancient Chinese poetry popular in modern Japan.
https://matome.naver.jp/odai/2141574836629656901

By looking at kanji, I understand the meaning sometimes.
During high school, when a friend asked the way in Chinese person, She could teach the way by seeing his writing kanji.
However, there are kanji whose meanings are completely different between Japanese and Chinese.
For example, 手紙.
In Japanese, it means letter.
In Chinese, it means toilet paper.
Although traditional Chinese（繁体字） is easy to understand, Simplified Chinese（簡体字） is difficult to understand.
Previously, when I did not understand Simplified Chinese, I used this site for a bit of translation at work.
http://www.jcdic.com/chinese_convert/