Of course there is GAP in future trading.When it hits Sunday evening 6:00pm, whatever news happened in the weekend, the index future (ES etc) price can be dramatically up or down from the close on previous Friday.
My charts rarely ever show what you would call a "gap". You mean a jump or drop in bid/ask at the market open by many many ticks? *shrugs* That is just a whole boatload of buy or sell limit orders being filled because they were placed before the market closed, or market-on-open orders placed while it was closed? That is not a "gap". The market is working as intended, yes? It is just like 3-4 years ago in the winter months when NG reports would come out at 10:30 ET Thursday and the thing would flail 100 ticks in an instant. Literally, an instant. So why was that never considered a "gap"? It is not a gap, it is just market dynamics.
If ES opened 26 points (=104 ticks) higher than the previous session ($1300 for once contract), do you call it a gap? Of course it is not so often.
If there is no trading taking place in futures and prices open higher or lower than the previous Friday's price, how can there NOT be a gap in the futures? Are we playing word games now? And your comparison to an intra-day NG 100 tick spike is still not apropos since prices are trading thru the entire 100 tick range. How are you not grasping this concept?
Friday, April 21 - Sunday/Monday, April 24, 2017 is a good example of that scenario. It eventually closed the "gap" on May 19, 2017, but ran roughly 50 pts higher before reversing.
Gaps are very visible when charting regular trading hours. If charts are 24hr, gaps (like you are referring to) will be few and generally not very wide. I use both RTH and 24hr charts. I know exactly the gaps you refer.
This is the lightest overnight volume of the year. Lets see how the day session pans out. What...is everyone waiting on Apple earnings. The Fed maybe, is the Fed going to hike in May to show the market it means business.
Find it hard to believe that we are still trying to define a gap on a trading site? These are the basics .. Investopedia is a nice place to start for those trying to wet their beaks... It`s called due diligence. https://www.investopedia.com/terms/g/gap.asp
Keep in mind alot of these folks trade on UK betting sites. Its like they use synthetic price quotes. Reminds me of bucket shops.