Where can I find the official Shenzen Special Economic Zone Tourism Visa details?

In fact, there are some China visa policies since 2013, and one of them is the Visa Exemption for Pearl River Delta RegionVisa Free To China, saying that:

Visitors travelling in a group, upon arrival in Hong Kong, can get a group Visa or 144-hour Convenient Visa to travel to Guangdong Province. This is a separate piece of paper (not attached to any passport), which requires that group members enter and exit China together.

Foreign visitors in Hong Kong can visit Guangdong Province for a maximum of 144 hours (6 days) via entry ports in Guangzhou, Shenzhen, Zhuhai, Foshan, Dongguan, Zhongshan, Jiangmen, Zhaoqing, Huizhou and Shantou. There is a choice of ports of entry or exit in Guangdong Province but you must enter and leave the areas together via the above-stated ports of entry.

Applications & Conditions:

• Visitors must join a tour group organized by a registered Hong Kong or Macau Travel Agent and must travel in a group consisting of a minimum 3 people and a maximum of 40 people.
• The group you have joined is organized by a registered travel agency.
• You are a citizen holding a passport issued by one of the nations
  with diplomatic relations with China.
• You don’t have any intentions on staying in the Pearl River Delta
  Region for more than 6 days.

You can find those in several different places, one of them being here, the Macau website of the Chinese min. of foreign affairs. The issue with this regulation is that it is changing from time to time and those changes are usually NOT reflected on any website. This is impossible because the changes happen too quickly, are often imposed only temporarily (as during the Olympics) and last but not least because many official Chinese government websites are too slow updating their websites in Chinese, let alone in English.

What is notable about this visa is that normally you should show up with some reason why you could not get a normal visa instead. If you can show an invitation from a Chinese organization that obviously arrived too late, you are more likely to get one than if you show up there and claim that you want to go groceries shopping or simply tourism.

If you have a confirmation from a Chinese party or the like, I would still recommend you to call either a Hong Kong travel agent or the border office itself to confirm that you are not barred by default because there is a current issue between China and your home country that would disable you from getting a visa.

This is it

http://www.olinorwell.com/how-to-visit-china-without-a-visa-shenzhen-5-day-visa-from-hong-kong/

5 day “visa on arrival” ??? (kind of) via walking across the Hong Kong border (I remember when I looked a few months ago) in Shenzhen at Futian border where you can exit HK, go upstairs and pay like 1000 RMB and get a 5 day visa. Not 100% sure, but they might exclude Americans from this policy. Technically you are supposed to only stay in Shenzhen because its a Special Economic Zone but who really knows. Just remember to leave on day 5.