Great news if you will be travelling with kids aged 6 - 14 in Germany

German national rail operator DB isn't solely refreshing its timetable at the annual timetable change on December 12th, as from this date it's also introducing a new child ticket policy for long-distance rail journeys.
The change is that if an adult (on German railways an adult is a person aged 15 and over) buys a ticket for journey by an express train (EC, IC and ICE), they can now take up to four children aged 6 - 14 with them at no additional charge.
The previous policy was that the adult needed to be a parent, or grandparent, but this requirement has now been dropped.

The ages of the chidren will need to be entered when booking, so you can't just turn up at the station and hop on board; the kids will still require tickets, but in effect they will be complimentary.

These new terms also apply to 1st class tickets and it doesn't matter which type of ticket is chosen.
So, if for example, you'll be flying in to Frankfurt for a holiday and want to head on to Berlin by train, the total ticket cost of 1 x adult and 4 x kids aged 6-14 travelling 1st class can be as low as €29.90.

Children aged 5 and under still travel for free on all German trains; and on the Regio and S-Bahn trains the former child ticket policy applies, namely a parent or grandparent can take up to four children aged 6 - 14 with them a no charge.

The 2nd class tickets won't come with seat reservations assigned, as that is standard in Germany, but a family reservation which includes up to five people, has a flat rate of €8.
This is a saving of more than €10 compared with paying for five individual seat reservation fees.
On ICE trains, if it hasn't already been booked, this €8 fee covers the cost of travelling in the
family compartment.

The new info on the DB child tickets guide focuses on the new policy (no parent/grandparent relationship required) being available on long-distance journeys, but it doesn't define what long-distance is.
Therefore SMTJ looked up some of the shorter distance journeys within Germany by EC, IC and ICE trains and these new child ticket terms were available, so it seems that these new child ticket terms apply to any booking on DB, for a journey by these types of train.

The new child ticket terms also seeming apply to bookings on DB (and at German stations) for international journeys by EC, IC and ICE trains.
The terms of 1 Adult = 4 x kids for free matches what the Austrian rail operator OBB offers, when booking its Sparscheine tickets for journeys between Austria and Germany; but booking on DB will now be a money saver when travelling with kids, regardless of family relationship, on these specific trains between Germany and Belgium, Czechia, Denmark, Italy and Switzerland.
Note that these new terms do not apply to journeys by Thalys trains on the Germany - Bruxelles - Paris route, or the DB-SNCF services between Germany and Paris; including the ICE trains on this route.